diff --git a/src/gc.h b/src/gc.h
index 93ab8c14dbb23d..69564739ffb807 100644
--- a/src/gc.h
+++ b/src/gc.h
@@ -230,14 +230,14 @@ STATIC_INLINE jl_gc_pagemeta_t *pop_lf_page_metadata_back(jl_gc_global_page_pool
 }
 
 #ifdef _P64
-#define REGION0_PG_COUNT (1 << 16)
+#define REGION0_PG_COUNT (1 << 14)
 #define REGION1_PG_COUNT (1 << 16)
 #define REGION2_PG_COUNT (1 << 18)
 #define REGION0_INDEX(p) (((uintptr_t)(p) >> GC_PAGE_LG2) & 0xFFFF) // shift by GC_PAGE_LG2
 #define REGION1_INDEX(p) (((uintptr_t)(p) >> 30) & 0xFFFF)
 #define REGION_INDEX(p)  (((uintptr_t)(p) >> 46) & 0x3FFFF)
 #else
-#define REGION0_PG_COUNT (1 << 8)
+#define REGION0_PG_COUNT (1 << 6)
 #define REGION1_PG_COUNT (1 << 10)
 #define REGION2_PG_COUNT (1 << 0)
 #define REGION0_INDEX(p) (((uintptr_t)(p) >> GC_PAGE_LG2) & 0xFF) // shift by GC_PAGE_LG2
diff --git a/src/julia_internal.h b/src/julia_internal.h
index a6b6f9a0c4c5d9..51b27747c9ce9f 100644
--- a/src/julia_internal.h
+++ b/src/julia_internal.h
@@ -346,7 +346,6 @@ void gc_sweep_sysimg(void);
 
 
 // pools are 65528 bytes large (GC_POOL_SZ - GC_PAGE_OFFSET)
-// TODO update table for 64k size
 static const int jl_gc_sizeclasses[] = {
 #ifdef _P64
     8,
@@ -370,18 +369,17 @@ static const int jl_gc_sizeclasses[] = {
 
     // rng = 60:-4:32 (8 pools)
     272, 288, 304, 336, 368, 400, 448, 496,
-//   60,  56,  53,  48,  44,  40,  36,  33, /pool
-//   64, 256, 272, 256, 192, 384, 256,  16, bytes lost
-
+    // 240,  227,  215,  195,  178,  163,  146,  132, /pool
+    // 248,  152,  168,  8,  24,  328,  120,  56, bytes lost
     // rng = 30:-2:16 (8 pools)
     544, 576, 624, 672, 736, 816, 896, 1008,
-//   30,  28,  26,  24,  22,  20,  18,  16, /pool
-//   64, 256, 160, 256, 192,  64, 256, 256, bytes lost
+    // 120,  113,  105,  97,  89,  80,  73,  65, /pool
+    // 248,  440,  8,  344,  24,  248,  120,  8, bytes lost
 
     // rng = 15:-1:8 (8 pools)
     1088, 1168, 1248, 1360, 1488, 1632, 1808, 2032
-//    15,   14,   13,   12,   11,   10,    9,    8, /pool
-//    64,   32,  160,   64,   16,   64,  112,  128, bytes lost
+    // 60,  56,  52,  48,  44,  40,  36,  32, /pool
+    // 248,  120,  632,  248,  56,  248,  440,  504, bytes lost
 };
 static_assert(sizeof(jl_gc_sizeclasses) / sizeof(jl_gc_sizeclasses[0]) == JL_GC_N_POOLS, "");