diff --git a/src/discof/bank/fd_bank_tile.c b/src/discof/bank/fd_bank_tile.c
index e5c2101040f..11ce731f530 100644
--- a/src/discof/bank/fd_bank_tile.c
+++ b/src/discof/bank/fd_bank_tile.c
@@ -46,6 +46,8 @@ typedef struct {
   fd_banks_t * banks;
   fd_spad_t *  exec_spad;
 
+  fd_writable_acc_buf_t writable_acc_arr[ FD_RUNTIME_MAX_WRITABLE_ACCOUNTS_PER_TRANSACTION ];
+
   fd_exec_txn_ctx_t txn_ctx[1];
 
   struct {
@@ -62,11 +64,11 @@ FD_FN_PURE static inline ulong
 scratch_footprint( fd_topo_tile_t const * tile ) {
   (void)tile;
   ulong l = FD_LAYOUT_INIT;
-  l = FD_LAYOUT_APPEND( l, alignof( fd_bank_ctx_t ), sizeof( fd_bank_ctx_t ) );
-  l = FD_LAYOUT_APPEND( l, FD_BLAKE3_ALIGN,          FD_BLAKE3_FOOTPRINT );
-  l = FD_LAYOUT_APPEND( l, FD_BMTREE_COMMIT_ALIGN,   FD_BMTREE_COMMIT_FOOTPRINT(0) );
-  l = FD_LAYOUT_APPEND( l, FD_SPAD_ALIGN,            FD_SPAD_FOOTPRINT( FD_RUNTIME_TRANSACTION_EXECUTION_FOOTPRINT_DEFAULT ) );
-  l = FD_LAYOUT_APPEND( l, fd_txncache_align(),      fd_txncache_footprint( tile->bank.max_live_slots ) );
+  l = FD_LAYOUT_APPEND( l, alignof(fd_bank_ctx_t), sizeof(fd_bank_ctx_t) );
+  l = FD_LAYOUT_APPEND( l, FD_BLAKE3_ALIGN,        FD_BLAKE3_FOOTPRINT );
+  l = FD_LAYOUT_APPEND( l, FD_BMTREE_COMMIT_ALIGN, FD_BMTREE_COMMIT_FOOTPRINT(0) );
+  l = FD_LAYOUT_APPEND( l, FD_SPAD_ALIGN,          FD_SPAD_FOOTPRINT( FD_RUNTIME_TRANSACTION_EXECUTION_FOOTPRINT_DEFAULT ) );
+  l = FD_LAYOUT_APPEND( l, fd_txncache_align(),    fd_txncache_footprint( tile->bank.max_live_slots ) );
   return FD_LAYOUT_FINI( l, scratch_align() );
 }
 
@@ -161,7 +163,7 @@ handle_microblock( fd_bank_ctx_t *     ctx,
 
     txn->flags &= ~FD_TXN_P_FLAGS_SANITIZE_SUCCESS;
 
-    int err = fd_runtime_prepare_and_execute_txn( ctx->banks, ctx->_bank_idx, txn_ctx, txn, ctx->exec_spad, NULL, 0 );
+    int err = fd_runtime_prepare_and_execute_txn( ctx->banks, ctx->_bank_idx, txn_ctx, txn, ctx->exec_spad, ctx->writable_acc_arr, NULL, 0 );
     if( FD_UNLIKELY( !(txn_ctx->flags & FD_TXN_P_FLAGS_SANITIZE_SUCCESS ) ) ) {
       ctx->metrics.txn_result[ fd_bank_err_from_runtime_err( err ) ]++;
       continue;
@@ -235,14 +237,14 @@ handle_microblock( fd_bank_ctx_t *     ctx,
        fork and diverge, so the link from here til PoH mixin must be
        completely reliable with nothing dropped.
 
-       fd_runtime_finalize_txn checks if the transaction fits into the
+       fd_runtime_commit_txn checks if the transaction fits into the
        block with the cost tracker.  If it doesn't fit, flags is set to
        zero.  A key invariant of the leader pipeline is that pack
        ensures all transactions must fit already, so it is a fatal error
        if that happens.  We cannot reject the transaction here as there
        would be no way to undo the partially applied changes to the bank
        in finalize anyway. */
-    fd_runtime_finalize_txn( ctx->txn_ctx->funk, txn_ctx->status_cache, txn_ctx->xid, txn_ctx, bank, NULL );
+    fd_runtime_commit_txn( ctx->txn_ctx->funk, txn_ctx->status_cache, txn_ctx->xid, txn_ctx, bank, NULL );
     FD_TEST( txn->flags );
   }
 
@@ -304,6 +306,7 @@ handle_bundle( fd_bank_ctx_t *     ctx,
                ulong               sz,
                ulong               begin_tspub,
                fd_stem_context_t * stem ) {
+
   uchar * dst = (uchar *)fd_chunk_to_laddr( ctx->out_mem, ctx->out_chunk );
   fd_txn_p_t * txns = (fd_txn_p_t *)dst;
 
@@ -326,7 +329,7 @@ handle_bundle( fd_bank_ctx_t *     ctx,
 
     fd_exec_txn_ctx_t txn_ctx[ 1 ]; // TODO ... bank manager ?
     txn->flags &= ~(FD_TXN_P_FLAGS_SANITIZE_SUCCESS | FD_TXN_P_FLAGS_EXECUTE_SUCCESS);
-    int err = fd_runtime_prepare_and_execute_txn( NULL, ULONG_MAX, txn_ctx, txn, NULL, NULL, 0 ); /* TODO ... */
+    int err = fd_runtime_prepare_and_execute_txn( NULL, ULONG_MAX, txn_ctx, txn, NULL, NULL, NULL, 0 ); /* TODO ... */
 
     transaction_err[ i ] = err;
     if( FD_UNLIKELY( err ) ) {
@@ -493,11 +496,11 @@ unprivileged_init( fd_topo_t *      topo,
   void * scratch = fd_topo_obj_laddr( topo, tile->tile_obj_id );
 
   FD_SCRATCH_ALLOC_INIT( l, scratch );
-  fd_bank_ctx_t * ctx = FD_SCRATCH_ALLOC_APPEND( l, alignof( fd_bank_ctx_t ), sizeof( fd_bank_ctx_t ) );
-  void * blake3       = FD_SCRATCH_ALLOC_APPEND( l, FD_BLAKE3_ALIGN,        FD_BLAKE3_FOOTPRINT );
-  void * bmtree       = FD_SCRATCH_ALLOC_APPEND( l, FD_BMTREE_COMMIT_ALIGN, FD_BMTREE_COMMIT_FOOTPRINT(0)      );
-  void * exec_spad    = FD_SCRATCH_ALLOC_APPEND( l, FD_SPAD_ALIGN,          FD_SPAD_FOOTPRINT( FD_RUNTIME_TRANSACTION_EXECUTION_FOOTPRINT_DEFAULT ) );
-  void * _txncache    = FD_SCRATCH_ALLOC_APPEND( l, fd_txncache_align(),    fd_txncache_footprint( tile->bank.max_live_slots ) );
+  fd_bank_ctx_t * ctx     = FD_SCRATCH_ALLOC_APPEND( l, alignof( fd_bank_ctx_t ), sizeof( fd_bank_ctx_t ) );
+  void * blake3           = FD_SCRATCH_ALLOC_APPEND( l, FD_BLAKE3_ALIGN,        FD_BLAKE3_FOOTPRINT );
+  void * bmtree           = FD_SCRATCH_ALLOC_APPEND( l, FD_BMTREE_COMMIT_ALIGN, FD_BMTREE_COMMIT_FOOTPRINT(0)      );
+  void * exec_spad        = FD_SCRATCH_ALLOC_APPEND( l, FD_SPAD_ALIGN,          FD_SPAD_FOOTPRINT( FD_RUNTIME_TRANSACTION_EXECUTION_FOOTPRINT_DEFAULT ) );
+  void * _txncache        = FD_SCRATCH_ALLOC_APPEND( l, fd_txncache_align(),    fd_txncache_footprint( tile->bank.max_live_slots ) );
 
 #define NONNULL( x ) (__extension__({                                        \
       __typeof__((x)) __x = (x);                                             \
diff --git a/src/discof/exec/fd_exec_tile.c b/src/discof/exec/fd_exec_tile.c
index d43a9a41f50..8fe2bbacd24 100644
--- a/src/discof/exec/fd_exec_tile.c
+++ b/src/discof/exec/fd_exec_tile.c
@@ -58,11 +58,16 @@ typedef struct fd_exec_tile_ctx {
 
   /* A transaction can be executed as long as there is a valid handle to
      a funk_txn and a bank. These are queried from fd_banks_t and
-     fd_funk_t.
-     TODO: These should probably be made read-only handles. */
+     fd_funk_t. */
   fd_banks_t *          banks;
   fd_funk_t             funk[ 1 ];
 
+  /* An array for writable accounts.  This is a staging buffer for
+     transactions.  The buffer is sized to be large enough to hold all
+     writable accounts for a transaction with 10MiB for each account
+     and up to 64 writable accounts. */
+  fd_writable_acc_buf_t writable_accounts_arr[ FD_RUNTIME_MAX_WRITABLE_ACCOUNTS_PER_TRANSACTION ];
+
   fd_txncache_t *       txncache;
 
   fd_vote_tracker_t *   vote_tracker;
@@ -121,6 +126,7 @@ during_frag( fd_exec_tile_ctx_t * ctx,
           ctx->txn_ctx,
           &txn->txn,
           ctx->exec_spad,
+          ctx->writable_accounts_arr,
           ctx->capture_ctx,
           1 );
     } else {
@@ -172,7 +178,7 @@ after_frag( fd_exec_tile_ctx_t * ctx,
       }
 
       if( FD_LIKELY( ctx->txn_ctx->flags & FD_TXN_P_FLAGS_EXECUTE_SUCCESS ) ) {
-          fd_runtime_finalize_txn(
+          fd_runtime_commit_txn(
             ctx->funk,
             ctx->txncache,
             &xid,
diff --git a/src/flamenco/runtime/Local.mk b/src/flamenco/runtime/Local.mk
index 6d9d6d8b6db..23ed0dfe3c8 100644
--- a/src/flamenco/runtime/Local.mk
+++ b/src/flamenco/runtime/Local.mk
@@ -39,8 +39,6 @@ $(call add-objs, tests/fd_dump_pb,fd_flamenco)
 
 $(call add-hdrs,fd_txn_account.h)
 $(call add-objs,fd_txn_account,fd_flamenco)
-$(call make-unit-test,test_txn_account,test_txn_account,fd_flamenco fd_funk fd_ballet fd_util)
-$(call run-unit-test,test_txn_account,)
 
 $(call add-hdrs,fd_bank.h)
 $(call add-objs,fd_bank,fd_flamenco)
diff --git a/src/flamenco/runtime/context/fd_exec_txn_ctx.h b/src/flamenco/runtime/context/fd_exec_txn_ctx.h
index 7c7233d3317..1c05ce56a6b 100644
--- a/src/flamenco/runtime/context/fd_exec_txn_ctx.h
+++ b/src/flamenco/runtime/context/fd_exec_txn_ctx.h
@@ -10,6 +10,7 @@
 #include "../../../funk/fd_funk.h"
 #include "../fd_compute_budget_details.h"
 #include "../../../disco/pack/fd_microblock.h"
+#include "../fd_runtime_const.h"
 
 /* Return data for syscalls */
 
@@ -21,6 +22,12 @@ struct fd_txn_return_data {
 
 typedef struct fd_txn_return_data fd_txn_return_data_t;
 
+/* TODO:FIXME: magic number for alignment*/
+struct __attribute__((aligned(8UL))) fd_writable_acc_buf {
+  uchar mem[ FD_RUNTIME_ACC_SZ_MAX ];
+};
+typedef struct fd_writable_acc_buf fd_writable_acc_buf_t;
+
 /* fd_exec_txn_ctx_t is the context needed to execute a transaction. */
 
 /* An entry in the instruction trace */
@@ -63,6 +70,8 @@ struct fd_exec_txn_ctx {
   fd_spad_t *                          spad;                                        /* Sized out to handle the worst case footprint of single transaction execution. */
   fd_wksp_t *                          spad_wksp;                                   /* Workspace for the spad. */
 
+  fd_writable_acc_buf_t *              writable_accounts_arr;
+
   fd_compute_budget_details_t          compute_budget_details;                      /* Compute budget details */
 
   /* Fields below here are not guaranteed to be local joins in txn execution. */
diff --git a/src/flamenco/runtime/fd_executor.c b/src/flamenco/runtime/fd_executor.c
index 9b0afcf0486..8eb981a3240 100644
--- a/src/flamenco/runtime/fd_executor.c
+++ b/src/flamenco/runtime/fd_executor.c
@@ -952,11 +952,11 @@ fd_executor_create_rollback_fee_payer_account( fd_exec_txn_ctx_t * txn_ctx,
     ulong  data_len       = fd_txn_account_get_data_len( &txn_ctx->accounts[FD_FEE_PAYER_TXN_IDX] );
     void * fee_payer_data = fd_spad_alloc( txn_ctx->spad, FD_ACCOUNT_REC_ALIGN, sizeof(fd_account_meta_t) + data_len );
     fd_memcpy( fee_payer_data, (uchar *)meta, sizeof(fd_account_meta_t) + data_len );
-    if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
+    if( FD_UNLIKELY( !fd_txn_account_new(
           txn_ctx->rollback_fee_payer_account,
           fee_payer_key,
           (fd_account_meta_t *)fee_payer_data,
-          1 ), txn_ctx->spad_wksp ) ) ) {
+          1 ) ) ) {
       FD_LOG_CRIT(( "Failed to join txn account" ));
     }
 
@@ -1420,7 +1420,6 @@ fd_executor_setup_txn_account( fd_exec_txn_ctx_t * txn_ctx,
 
   int                 is_writable  = fd_exec_txn_ctx_account_is_writable_idx( txn_ctx, idx ) || idx==FD_FEE_PAYER_TXN_IDX;
   fd_account_meta_t * account_meta = NULL;
-  fd_wksp_t *         data_wksp    = NULL;
 
   if( is_writable ) {
     /* If the account is writable or a fee payer, then we need to create
@@ -1428,7 +1427,7 @@ fd_executor_setup_txn_account( fd_exec_txn_ctx_t * txn_ctx,
        copy the account data into the staging area; otherwise, we need to
        initialize a new metadata. */
 
-    uchar * new_raw_data = fd_spad_alloc( txn_ctx->spad, FD_ACCOUNT_REC_ALIGN, FD_ACC_TOT_SZ_MAX );
+    uchar * new_raw_data = txn_ctx->writable_accounts_arr[idx].mem;
     ulong   dlen         = !!meta ? meta->dlen : 0UL;
 
     if( FD_LIKELY( meta ) ) {
@@ -1440,7 +1439,6 @@ fd_executor_setup_txn_account( fd_exec_txn_ctx_t * txn_ctx,
     }
 
     account_meta = (fd_account_meta_t *)new_raw_data;
-    data_wksp    = txn_ctx->spad_wksp;
 
   } else {
     /* If the account is not writable, then we can simply initialize
@@ -1450,20 +1448,18 @@ fd_executor_setup_txn_account( fd_exec_txn_ctx_t * txn_ctx,
 
     if( FD_LIKELY( err==FD_ACC_MGR_SUCCESS ) ) {
       account_meta = (fd_account_meta_t *)meta;
-      data_wksp    = fd_funk_wksp( txn_ctx->funk );
     } else {
       uchar * mem = fd_spad_alloc( txn_ctx->spad, FD_TXN_ACCOUNT_ALIGN, sizeof(fd_account_meta_t) );
       account_meta = (fd_account_meta_t *)mem;
-      data_wksp    = txn_ctx->spad_wksp;
       fd_account_meta_init( account_meta );
     }
   }
 
-  if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
+  if( FD_UNLIKELY( !fd_txn_account_new(
       txn_account,
       acc,
       account_meta,
-      is_writable ), data_wksp ) ) ) {
+      is_writable ) ) ) {
     FD_LOG_CRIT(( "Failed to join txn account" ));
   }
 
diff --git a/src/flamenco/runtime/fd_runtime.c b/src/flamenco/runtime/fd_runtime.c
index 1594e4082e8..8b8938537a7 100644
--- a/src/flamenco/runtime/fd_runtime.c
+++ b/src/flamenco/runtime/fd_runtime.c
@@ -1033,14 +1033,8 @@ fd_runtime_save_account( fd_funk_t *               funk,
                          fd_funk_txn_xid_t const * xid,
                          fd_txn_account_t *        account,
                          fd_bank_t *               bank,
-                         fd_wksp_t *               acc_data_wksp,
                          fd_capture_ctx_t *        capture_ctx ) {
 
-  /* Join the transaction account */
-  if( FD_UNLIKELY( !fd_txn_account_join( account, acc_data_wksp ) ) ) {
-    FD_LOG_CRIT(( "fd_runtime_save_account: failed to join account" ));
-  }
-
   /* Look up the previous version of the account from Funk */
   FD_TXN_ACCOUNT_DECL( previous_account_version );
   int err = fd_txn_account_init_from_funk_readonly( previous_account_version, account->pubkey, funk, xid );
@@ -1071,18 +1065,14 @@ fd_runtime_save_account( fd_funk_t *               funk,
   fd_runtime_finalize_account( funk, xid, account );
 }
 
-/* fd_runtime_finalize_txn is a helper used by the non-tpool transaction
-   executor to finalize borrowed account changes back into funk. It also
-   handles txncache insertion and updates to the vote/stake cache.
-   TODO: This function should probably be moved to fd_executor.c. */
 
 void
-fd_runtime_finalize_txn( fd_funk_t *               funk,
-                         fd_txncache_t *           txncache,
-                         fd_funk_txn_xid_t const * xid,
-                         fd_exec_txn_ctx_t *       txn_ctx,
-                         fd_bank_t *               bank,
-                         fd_capture_ctx_t *        capture_ctx ) {
+fd_runtime_commit_txn( fd_funk_t *               funk,
+                       fd_txncache_t *           txncache,
+                       fd_funk_txn_xid_t const * xid,
+                       fd_exec_txn_ctx_t *       txn_ctx,
+                       fd_bank_t *               bank,
+                       fd_capture_ctx_t *        capture_ctx ) {
 
   /* Collect fees */
   FD_ATOMIC_FETCH_AND_ADD( fd_bank_txn_count_modify( bank ), 1UL );
@@ -1107,12 +1097,12 @@ fd_runtime_finalize_txn( fd_funk_t *               funk,
 
        We should always rollback the nonce account first. Note that the nonce account may be the fee payer (case 2). */
     if( txn_ctx->nonce_account_idx_in_txn!=ULONG_MAX ) {
-      fd_runtime_save_account( funk, xid, txn_ctx->rollback_nonce_account, bank, txn_ctx->spad_wksp, capture_ctx );
+      fd_runtime_save_account( funk, xid, txn_ctx->rollback_nonce_account, bank, capture_ctx );
     }
 
     /* Now, we must only save the fee payer if the nonce account was not the fee payer (because that was already saved above) */
     if( FD_LIKELY( txn_ctx->nonce_account_idx_in_txn!=FD_FEE_PAYER_TXN_IDX ) ) {
-      fd_runtime_save_account( funk, xid, txn_ctx->rollback_fee_payer_account, bank, txn_ctx->spad_wksp, capture_ctx );
+      fd_runtime_save_account( funk, xid, txn_ctx->rollback_fee_payer_account, bank, capture_ctx );
     }
   } else {
 
@@ -1125,10 +1115,7 @@ fd_runtime_finalize_txn( fd_funk_t *               funk,
         continue;
       }
 
-      fd_txn_account_t * acc_rec = fd_txn_account_join( &txn_ctx->accounts[i], txn_ctx->spad_wksp );
-      if( FD_UNLIKELY( !acc_rec ) ) {
-        FD_LOG_CRIT(( "fd_runtime_finalize_txn: failed to join account at idx %u", i ));
-      }
+      fd_txn_account_t * acc_rec = &txn_ctx->accounts[i];
 
       if( dirty_vote_acc && 0==memcmp( fd_txn_account_get_owner( acc_rec ), &fd_solana_vote_program_id, sizeof(fd_pubkey_t) ) ) {
         fd_vote_store_account( acc_rec, bank );
@@ -1142,7 +1129,7 @@ fd_runtime_finalize_txn( fd_funk_t *               funk,
          cache updates have been applied. */
       fd_executor_reclaim_account( txn_ctx, &txn_ctx->accounts[i] );
 
-      fd_runtime_save_account( funk, xid, &txn_ctx->accounts[i], bank, txn_ctx->spad_wksp, capture_ctx );
+      fd_runtime_save_account( funk, xid, &txn_ctx->accounts[i], bank, capture_ctx );
     }
 
     /* We need to queue any existing program accounts that may have
@@ -1196,13 +1183,14 @@ fd_runtime_finalize_txn( fd_funk_t *               funk,
 }
 
 int
-fd_runtime_prepare_and_execute_txn( fd_banks_t *        banks,
-                                    ulong               bank_idx,
-                                    fd_exec_txn_ctx_t * txn_ctx,
-                                    fd_txn_p_t *        txn,
-                                    fd_spad_t *         exec_spad,
-                                    fd_capture_ctx_t *  capture_ctx,
-                                    uchar               do_sigverify ) {
+fd_runtime_prepare_and_execute_txn( fd_banks_t *            banks,
+                                    ulong                   bank_idx,
+                                    fd_exec_txn_ctx_t *     txn_ctx,
+                                    fd_txn_p_t *            txn,
+                                    fd_spad_t *             exec_spad,
+                                    fd_writable_acc_buf_t * writable_accounts_arr,
+                                    fd_capture_ctx_t *      capture_ctx,
+                                    uchar                   do_sigverify ) {
   FD_SPAD_FRAME_BEGIN( exec_spad ) {
   int exec_res = 0;
 
@@ -1222,6 +1210,7 @@ fd_runtime_prepare_and_execute_txn( fd_banks_t *        banks,
   txn_ctx->xid[0]                = (fd_funk_txn_xid_t){ .ul = { slot, slot } };
   txn_ctx->capture_ctx           = capture_ctx;
   txn_ctx->txn                   = *txn;
+  txn_ctx->writable_accounts_arr = writable_accounts_arr;
 
   txn_ctx->flags = FD_TXN_P_FLAGS_SANITIZE_SUCCESS;
   fd_exec_txn_ctx_setup_basic( txn_ctx );
diff --git a/src/flamenco/runtime/fd_runtime.h b/src/flamenco/runtime/fd_runtime.h
index dccfe81ef40..5b9d10d1c3b 100644
--- a/src/flamenco/runtime/fd_runtime.h
+++ b/src/flamenco/runtime/fd_runtime.h
@@ -451,21 +451,22 @@ fd_runtime_pre_execute_check( fd_exec_txn_ctx_t * txn_ctx );
    transaction. */
 
 int
-fd_runtime_prepare_and_execute_txn( fd_banks_t *        banks,
-                                    ulong               bank_idx,
-                                    fd_exec_txn_ctx_t * txn_ctx,
-                                    fd_txn_p_t *        txn,
-                                    fd_spad_t *         exec_spad,
-                                    fd_capture_ctx_t *  capture_ctx,
-                                    uchar               do_sigverify );
+fd_runtime_prepare_and_execute_txn( fd_banks_t *            banks,
+                                    ulong                   bank_idx,
+                                    fd_exec_txn_ctx_t *     txn_ctx,
+                                    fd_txn_p_t *            txn,
+                                    fd_spad_t *             exec_spad,
+                                    fd_writable_acc_buf_t * writable_accounts_arr,
+                                    fd_capture_ctx_t *      capture_ctx,
+                                    uchar                   do_sigverify );
 
 void
-fd_runtime_finalize_txn( fd_funk_t *               funk,
-                         fd_txncache_t *           txncache,
-                         fd_funk_txn_xid_t const * xid,
-                         fd_exec_txn_ctx_t *       txn_ctx,
-                         fd_bank_t *               bank,
-                         fd_capture_ctx_t *        capture_ctx );
+fd_runtime_commit_txn( fd_funk_t *               funk,
+                       fd_txncache_t *           txncache,
+                       fd_funk_txn_xid_t const * xid,
+                       fd_exec_txn_ctx_t *       txn_ctx,
+                       fd_bank_t *               bank,
+                       fd_capture_ctx_t *        capture_ctx );
 
 /* Epoch Boundary *************************************************************/
 
diff --git a/src/flamenco/runtime/fd_txn_account.c b/src/flamenco/runtime/fd_txn_account.c
index 4569df61492..99058e126b1 100644
--- a/src/flamenco/runtime/fd_txn_account.c
+++ b/src/flamenco/runtime/fd_txn_account.c
@@ -1,7 +1,7 @@
 #include "fd_txn_account.h"
 #include "fd_runtime.h"
 
-void *
+fd_txn_account_t *
 fd_txn_account_new( void *              mem,
                     fd_pubkey_t const * pubkey,
                     fd_account_meta_t * meta,
@@ -30,27 +30,12 @@ fd_txn_account_new( void *              mem,
 
   fd_memcpy( txn_account->pubkey, pubkey, sizeof(fd_pubkey_t) );
 
-  fd_wksp_t * wksp = fd_wksp_containing( meta );
-
   txn_account->magic             = FD_TXN_ACCOUNT_MAGIC;
-
   txn_account->starting_dlen     = meta->dlen;
   txn_account->starting_lamports = meta->lamports;
 
   uchar * data = (uchar *)meta + sizeof(fd_account_meta_t);
 
-  txn_account->meta_gaddr = fd_wksp_gaddr( wksp, meta );
-  if( FD_UNLIKELY( !txn_account->meta_gaddr ) ) {
-    FD_LOG_WARNING(( "meta_gaddr is 0" ));
-    return NULL;
-  }
-
-  txn_account->data_gaddr = fd_wksp_gaddr( wksp, data );
-  if( FD_UNLIKELY( !txn_account->data_gaddr ) ) {
-    FD_LOG_WARNING(( "data_gaddr is 0" ));
-    return NULL;
-  }
-
   txn_account->meta       = meta;
   txn_account->data       = data;
   txn_account->is_mutable = is_mutable;
@@ -58,93 +43,6 @@ fd_txn_account_new( void *              mem,
   return mem;
 }
 
-fd_txn_account_t *
-fd_txn_account_join( void * mem, fd_wksp_t * data_wksp ) {
-  if( FD_UNLIKELY( !mem ) ) {
-    FD_LOG_WARNING(( "NULL mem" ));
-    return NULL;
-  }
-
-  if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)mem, alignof(fd_txn_account_t) ) ) ) {
-    FD_LOG_WARNING(( "misaligned mem" ));
-    return NULL;
-  }
-
-  if( FD_UNLIKELY( !data_wksp ) ) {
-    FD_LOG_WARNING(( "NULL data_wksp" ));
-    return NULL;
-  }
-
-  fd_txn_account_t * txn_account = (fd_txn_account_t *)mem;
-
-  if( FD_UNLIKELY( txn_account->magic != FD_TXN_ACCOUNT_MAGIC ) ) {
-    FD_LOG_WARNING(( "wrong magic" ));
-    return NULL;
-  }
-
-  if( FD_UNLIKELY( txn_account->meta_gaddr==0UL ) ) {
-    FD_LOG_WARNING(( "`meta gaddr is 0" ));
-    return NULL;
-  }
-
-  txn_account->meta = fd_wksp_laddr( data_wksp, txn_account->meta_gaddr );
-  if( FD_UNLIKELY( !txn_account->meta ) ) {
-    FD_LOG_WARNING(( "meta is NULL" ));
-    return NULL;
-  }
-
-  txn_account->data = fd_wksp_laddr( data_wksp, txn_account->data_gaddr );
-  if( FD_UNLIKELY( !txn_account->data && txn_account->meta->dlen ) ) {
-    FD_LOG_WARNING(( "data is NULL" ));
-    return NULL;
-  }
-
-  return txn_account;
-}
-
-void *
-fd_txn_account_leave( fd_txn_account_t * acct ) {
-
-  if( FD_UNLIKELY( !acct ) ) {
-    FD_LOG_WARNING(( "NULL acct" ));
-    return NULL;
-  }
-
-  if( FD_UNLIKELY( acct->magic != FD_TXN_ACCOUNT_MAGIC ) ) {
-    FD_LOG_WARNING(( "wrong magic" ));
-    return NULL;
-  }
-
-  acct->meta = NULL;
-  acct->data = NULL;
-
-  return acct;
-}
-
-void *
-fd_txn_account_delete( void * mem ) {
-  if( FD_UNLIKELY( !mem ) ) {
-    FD_LOG_WARNING(( "NULL mem" ));
-    return NULL;
-  }
-
-  if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)mem, alignof(fd_txn_account_t) ) ) ) {
-    FD_LOG_WARNING(( "misaligned mem" ));
-    return NULL;
-  }
-
-  fd_txn_account_t * txn_account = (fd_txn_account_t *)mem;
-
-  if( FD_UNLIKELY( txn_account->magic != FD_TXN_ACCOUNT_MAGIC ) ) {
-    FD_LOG_WARNING(( "wrong magic" ));
-    return NULL;
-  }
-
-  txn_account->magic = 0UL;
-
-  return mem;
-}
-
 /* Factory constructors from funk */
 
 int
@@ -166,11 +64,11 @@ fd_txn_account_init_from_funk_readonly( fd_txn_account_t *        acct,
     return err;
   }
 
-  if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
+  if( FD_UNLIKELY( !fd_txn_account_new(
         acct,
         pubkey,
         (fd_account_meta_t *)meta,
-        0 ), fd_funk_wksp( funk ) ) ) ) {
+        0 ) ) ) {
     FD_LOG_CRIT(( "Failed to join txn account" ));
   }
 
@@ -206,11 +104,11 @@ fd_txn_account_init_from_funk_mutable( fd_txn_account_t *        acct,
      prepared_rec field so that any created records can be published
      with fd_txn_account_mutable_fini. */
 
-  if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
+  if( FD_UNLIKELY( !fd_txn_account_new(
         acct,
         pubkey,
         (fd_account_meta_t *)meta,
-        1 ), fd_funk_wksp( funk ) ) ) ) {
+        1 ) ) ) {
     FD_LOG_CRIT(( "Failed to join txn account" ));
   }
 
diff --git a/src/flamenco/runtime/fd_txn_account.h b/src/flamenco/runtime/fd_txn_account.h
index 85a89eb4e6b..33f9108080f 100644
--- a/src/flamenco/runtime/fd_txn_account.h
+++ b/src/flamenco/runtime/fd_txn_account.h
@@ -64,40 +64,12 @@ FD_PROTOTYPES_BEGIN
    After a successful call to fd_txn_account_new, the object will now
    own the account's metadata and data. */
 
-void *
+fd_txn_account_t *
 fd_txn_account_new( void *              mem,
                     fd_pubkey_t const * pubkey,
                     fd_account_meta_t * meta,
                     int                 is_mutable );
 
-/* fd_txn_account_join joins a thread with an indepedent address space
-   to the memory region allocated by fd_txn_account_new. There can be
-   only ONE valid join per fd_txn_account_t object. If a _join is called
-   from one thread, it is implied that the object is no longer valid
-   on other threads.
-
-   TODO: When the new db is introduced, the wksp argument should be
-   removed in favor of using offsets into other data structures. */
-
-fd_txn_account_t *
-fd_txn_account_join( void * mem, fd_wksp_t * data_wksp );
-
-/* fd_txn_account_leave leaves a current local join and returns a
-   pointer to the underlying shared memory region. The fd_txn_account_t
-   will still own the account's metadata and data. */
-
-void *
-fd_txn_account_leave( fd_txn_account_t * acct );
-
-/* fd_txn_account_delete removes the memory layout for the
-   fd_txn_account_t object. It returns a pointer to the underlying
-   shared struct. Any attempts to join after a call to
-   fd_txn_account_delete will fail. The account's metadata and data
-   will be owned by the caller after the delete is called.  */
-
-void *
-fd_txn_account_delete( void * mem );
-
 /* Factory constructors from funk.
    TODO: These need to be removed when a new db is introduced and either
    replaced with a new factory constructor or removed entirely in favor
diff --git a/src/flamenco/runtime/program/fd_system_program_nonce.c b/src/flamenco/runtime/program/fd_system_program_nonce.c
index 156160874a4..a2472e7e611 100644
--- a/src/flamenco/runtime/program/fd_system_program_nonce.c
+++ b/src/flamenco/runtime/program/fd_system_program_nonce.c
@@ -1030,11 +1030,11 @@ fd_check_transaction_age( fd_exec_txn_ctx_t * txn_ctx ) {
         }
         fd_memcpy( borrowed_account_data, meta, sizeof(fd_account_meta_t)+acc_data_len );
 
-        if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
+        if( FD_UNLIKELY( !fd_txn_account_new(
               txn_ctx->rollback_nonce_account,
               &txn_ctx->account_keys[ instr_accts[ 0UL ] ],
               (fd_account_meta_t *)borrowed_account_data,
-              1 ), txn_ctx->spad_wksp ) ) ) {
+              1 ) ) ) {
           FD_LOG_CRIT(( "Failed to join txn account" ));
         }
 
diff --git a/src/flamenco/runtime/sysvar/fd_sysvar_instructions.c b/src/flamenco/runtime/sysvar/fd_sysvar_instructions.c
index 7bf04251136..1ce04b53c78 100644
--- a/src/flamenco/runtime/sysvar/fd_sysvar_instructions.c
+++ b/src/flamenco/runtime/sysvar/fd_sysvar_instructions.c
@@ -62,7 +62,7 @@ fd_sysvar_instructions_serialize_account( fd_exec_txn_ctx_t *      txn_ctx,
   if( !fd_txn_account_is_mutable( rec ) ) {
     uchar *             mem  = fd_spad_alloc( txn_ctx->spad, FD_TXN_ACCOUNT_ALIGN, sizeof(fd_account_meta_t) + serialized_sz );
     fd_account_meta_t * meta = (fd_account_meta_t *)mem;
-    fd_txn_account_t *  acc  = fd_txn_account_join( fd_txn_account_new( rec, &fd_sysvar_instructions_id, meta, 1 ), txn_ctx->spad_wksp );
+    fd_txn_account_t *  acc  = fd_txn_account_new( rec, &fd_sysvar_instructions_id, meta, 1 );
     if( FD_UNLIKELY( !acc ) ) {
       FD_LOG_CRIT(( "Failed to join txn account" ));
     }
diff --git a/src/flamenco/runtime/test_txn_account.c b/src/flamenco/runtime/test_txn_account.c
deleted file mode 100644
index 4527798b690..00000000000
--- a/src/flamenco/runtime/test_txn_account.c
+++ /dev/null
@@ -1,89 +0,0 @@
-#include "fd_txn_account.h"
-#include "fd_acc_mgr.h"
-
-int
-main( int argc, char ** argv ) {
-  fd_boot( &argc, &argv );
-
-  char *      _page_sz = "gigantic";
-  ulong       numa_idx = fd_shmem_numa_idx( 0 );
-  fd_wksp_t * wksp     = fd_wksp_new_anonymous( fd_cstr_to_shmem_page_sz( _page_sz ),
-                                                1UL,
-                                                fd_shmem_cpu_idx( numa_idx ),
-                                                "wksp",
-                                                0UL );
-  void * tx_acc_mem = fd_wksp_alloc_laddr( wksp, FD_TXN_ACCOUNT_ALIGN, FD_TXN_ACCOUNT_FOOTPRINT, 1UL );
-  FD_TEST( tx_acc_mem );
-
-  fd_pubkey_t pubkey = { .ul = { 9, 10 } };
-
-  uchar * data  = fd_wksp_alloc_laddr( wksp, 1UL, 1000UL, 1UL );
-  uchar * data2 = fd_wksp_alloc_laddr( wksp, 1UL, 1000UL, 1UL );
-  fd_account_meta_t * meta = (fd_account_meta_t *)data;
-  fd_account_meta_init( meta );
-  meta->dlen = 100UL;
-  uchar * acc_data = fd_account_meta_get_data( meta );
-
-  FD_TEST( !fd_txn_account_new( NULL, &pubkey, meta, 0 ) );
-  FD_TEST( !fd_txn_account_new( tx_acc_mem, NULL, meta, 0 ) );
-  FD_TEST( !fd_txn_account_new( tx_acc_mem, &pubkey, NULL, 0 ) );
-
-  uchar * new_tx_account = fd_txn_account_new( tx_acc_mem, &pubkey, meta, 0 );
-  FD_TEST( new_tx_account );
-
-  FD_TEST( !fd_txn_account_join( NULL, wksp ) );
-  FD_TEST( !fd_txn_account_join( data2, wksp ) );
-  FD_TEST( !fd_txn_account_join( tx_acc_mem, NULL ) );
-  fd_txn_account_t * txn_account = fd_txn_account_join( tx_acc_mem, wksp );
-  FD_TEST( txn_account );
-
-  /* TODO: These tests do not enforce that the account is read-only
-     because the current impl calls FD_LOG_CRIT when the account is
-     not mutable but the caller calls a mutator. */
-
-  uchar null_hash[32] = { 0 };
-
-  FD_TEST( !fd_txn_account_is_mutable( txn_account ) );
-  FD_TEST( fd_txn_account_is_readonly( txn_account ) );
-  FD_TEST( fd_txn_account_get_data_len( txn_account ) == 100UL );
-  FD_TEST( fd_txn_account_get_lamports( txn_account ) == 0UL );
-  FD_TEST( fd_txn_account_get_rent_epoch( txn_account ) == ULONG_MAX );
-  FD_TEST( !memcmp( fd_txn_account_get_owner( txn_account ), null_hash, sizeof(null_hash) ) );
-  FD_TEST( fd_txn_account_get_meta( txn_account ) == meta );
-  FD_TEST( fd_txn_account_get_data( txn_account ) == acc_data );
-
-  FD_TEST( fd_txn_account_leave( txn_account ) );
-
-  FD_TEST( fd_txn_account_join( fd_txn_account_leave( txn_account ), wksp ) );
-  FD_TEST( !fd_txn_account_leave( NULL ) );
-
-  uchar * deleted_tx_account = fd_txn_account_delete( fd_txn_account_leave( txn_account ) );
-  FD_TEST( deleted_tx_account );
-  FD_TEST( !fd_txn_account_join( deleted_tx_account, wksp ) );
-  FD_TEST( !fd_txn_account_delete( NULL ) );
-
-  /* Repeat similar tests with a mutable account */
-
-  meta->dlen = 101UL;
-  txn_account = fd_txn_account_join( fd_txn_account_new( tx_acc_mem, &pubkey, meta, 1 ), wksp );
-  FD_TEST( txn_account );
-
-  FD_TEST( fd_txn_account_is_mutable( txn_account ) );
-  FD_TEST( !fd_txn_account_is_readonly( txn_account ) );
-  FD_TEST( fd_txn_account_get_data_len( txn_account ) == 101UL );
-  FD_TEST( fd_txn_account_get_lamports( txn_account ) == 0UL );
-
-  fd_txn_account_set_lamports( txn_account, 1000UL );
-  FD_TEST( fd_txn_account_get_lamports( txn_account ) == 1000UL );
-
-  FD_TEST( fd_txn_account_get_rent_epoch( txn_account ) == ULONG_MAX );
-
-  fd_txn_account_set_data_len( txn_account, 102UL );
-  FD_TEST( fd_txn_account_get_data_len( txn_account ) == 102UL );
-  FD_TEST( fd_txn_account_delete( fd_txn_account_leave( txn_account ) ) );
-
-  FD_LOG_NOTICE(( "pass" ));
-
-  fd_halt();
-  return 0;
-}
diff --git a/src/flamenco/runtime/tests/fd_block_harness.c b/src/flamenco/runtime/tests/fd_block_harness.c
index f325bb2c6d3..4e50cd04b5d 100644
--- a/src/flamenco/runtime/tests/fd_block_harness.c
+++ b/src/flamenco/runtime/tests/fd_block_harness.c
@@ -491,8 +491,8 @@ fd_runtime_fuzz_block_ctx_exec( fd_solfuzz_runner_t *      runner,
         break;
       }
 
-      /* Finalize the transaction */
-      fd_runtime_finalize_txn(
+      /* Commit the transaction */
+      fd_runtime_commit_txn(
           slot_ctx->funk,
           NULL,
           slot_ctx->xid,
diff --git a/src/flamenco/runtime/tests/fd_instr_harness.c b/src/flamenco/runtime/tests/fd_instr_harness.c
index 7235d903efa..6a435d68192 100644
--- a/src/flamenco/runtime/tests/fd_instr_harness.c
+++ b/src/flamenco/runtime/tests/fd_instr_harness.c
@@ -148,7 +148,7 @@ fd_runtime_fuzz_instr_ctx_create( fd_solfuzz_runner_t *                runner,
       ulong               dlen     = fd_txn_account_get_data_len( acc );
       fd_account_meta_t * meta     = (fd_account_meta_t *)data;
       fd_memcpy( data, fd_txn_account_get_meta( acc ), sizeof(fd_account_meta_t)+dlen );
-      if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new( acc, acc_key, meta, 0 ), txn_ctx->spad_wksp ) ) ) {
+      if( FD_UNLIKELY( !fd_txn_account_new( acc, acc_key, meta, 0 ) ) ) {
         FD_LOG_CRIT(( "Failed to join and new a txn account" ));
       }
     }
@@ -173,11 +173,7 @@ fd_runtime_fuzz_instr_ctx_create( fd_solfuzz_runner_t *                runner,
     fd_account_meta_t * meta = fd_spad_alloc( txn_ctx->spad, alignof(fd_account_meta_t), sizeof(fd_account_meta_t) );
     fd_account_meta_init( meta );
 
-    if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new(
-          program_acc,
-          program_key,
-          meta,
-          1 ), txn_ctx->spad_wksp ) ) ) {
+    if( FD_UNLIKELY( !fd_txn_account_new( program_acc, program_key, meta, 1 ) ) ) {
       FD_LOG_CRIT(( "Failed to join and new a txn account" ));
     }
 
@@ -199,7 +195,7 @@ fd_runtime_fuzz_instr_ctx_create( fd_solfuzz_runner_t *                runner,
       uchar * mem = fd_spad_alloc( txn_ctx->spad, FD_TXN_ACCOUNT_ALIGN, sizeof(fd_account_meta_t) );
       fd_account_meta_t * meta = (fd_account_meta_t *)mem;
       memset( meta, 0, sizeof(fd_account_meta_t) );
-      if( FD_UNLIKELY( !fd_txn_account_join( fd_txn_account_new( acc, acc_key, meta, 0 ), txn_ctx->spad_wksp ) ) ) {
+      if( FD_UNLIKELY( !fd_txn_account_new( acc, acc_key, meta, 0 ) ) ) {
         FD_LOG_CRIT(( "Failed to join and new a txn account" ));
       }
       continue;
diff --git a/src/flamenco/runtime/tests/fd_txn_harness.c b/src/flamenco/runtime/tests/fd_txn_harness.c
index 3c22189bb55..b9049dcbabc 100644
--- a/src/flamenco/runtime/tests/fd_txn_harness.c
+++ b/src/flamenco/runtime/tests/fd_txn_harness.c
@@ -347,12 +347,13 @@ fd_runtime_fuzz_txn_ctx_exec( fd_solfuzz_runner_t * runner,
                               int *                 exec_res ) {
 
   /* Setup the spad for account allocation */
-  uchar *             txn_ctx_mem        = fd_spad_alloc( runner->spad, FD_EXEC_TXN_CTX_ALIGN, FD_EXEC_TXN_CTX_FOOTPRINT );
-  fd_exec_txn_ctx_t * txn_ctx            = fd_exec_txn_ctx_join( fd_exec_txn_ctx_new( txn_ctx_mem ), runner->spad, fd_wksp_containing( runner->spad ) );
-  txn_ctx->flags                         = FD_TXN_P_FLAGS_SANITIZE_SUCCESS;
-  *txn_ctx->funk                         = *slot_ctx->funk;
-  txn_ctx->bank_hash_cmp                 = NULL;
-  txn_ctx->fuzz_config.enable_vm_tracing = runner->enable_vm_tracing;
+  uchar *             txn_ctx_mem          = fd_spad_alloc( runner->spad, FD_EXEC_TXN_CTX_ALIGN, FD_EXEC_TXN_CTX_FOOTPRINT );
+  fd_writable_acc_buf_t * writable_acc_arr = fd_spad_alloc( runner->spad, alignof(fd_writable_acc_buf_t), sizeof(fd_writable_acc_buf_t) * FD_RUNTIME_MAX_WRITABLE_ACCOUNTS_PER_TRANSACTION );
+  fd_exec_txn_ctx_t * txn_ctx              = fd_exec_txn_ctx_join( fd_exec_txn_ctx_new( txn_ctx_mem ), runner->spad, fd_wksp_containing( runner->spad ) );
+  txn_ctx->flags                           = FD_TXN_P_FLAGS_SANITIZE_SUCCESS;
+  *txn_ctx->funk                           = *slot_ctx->funk;
+  txn_ctx->bank_hash_cmp                   = NULL;
+  txn_ctx->fuzz_config.enable_vm_tracing   = runner->enable_vm_tracing;
 
   *exec_res = fd_runtime_prepare_and_execute_txn(
       slot_ctx->banks,
@@ -360,6 +361,7 @@ fd_runtime_fuzz_txn_ctx_exec( fd_solfuzz_runner_t * runner,
       txn_ctx,
       txn,
       runner->spad,
+      writable_acc_arr,
       NULL,
       0 );