diff --git a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
index dc0af274d..22059a382 100644
--- a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+++ b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
@@ -4395,8 +4395,8 @@ void OpDispatchBuilder::CMPXCHGPairOp(OpcodeArgs) {
   const uint8_t GPRSize = CTX->GetGPRSize();
   // REX.W used to determine if it is 16byte or 8byte
   // Unlike CMPXCHG, the destination can only be a memory location
+  uint8_t Size = Op->Flags & FEXCore::X86Tables::DecodeFlags::FLAG_REX_WIDENING ? 8 : 4;
 
-  const auto Size = GetSrcSize(Op);
   HandledLock = (Op->Flags & FEXCore::X86Tables::DecodeFlags::FLAG_LOCK) != 0;
   // If this is a memory location then we want the pointer to it
   OrderedNode *Src1 = LoadSource(GPRClass, Op, Op->Dest, Op->Flags, -1, false);
@@ -5797,9 +5797,14 @@ constexpr uint16_t PF_F2 = 3;
     {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_NONE, 6), 1, &OpDispatchBuilder::RDRANDOp<false>},
     {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_NONE, 7), 1, &OpDispatchBuilder::RDRANDOp<true>},
 
+    {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_F3, 1), 1, &OpDispatchBuilder::CMPXCHGPairOp},
+
+    {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_66, 1), 1, &OpDispatchBuilder::CMPXCHGPairOp},
     {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_66, 6), 1, &OpDispatchBuilder::RDRANDOp<false>},
     {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_66, 7), 1, &OpDispatchBuilder::RDRANDOp<true>},
 
+    {OPD(FEXCore::X86Tables::TYPE_GROUP_9, PF_F2, 1), 1, &OpDispatchBuilder::CMPXCHGPairOp},
+
     // GROUP 12
     {OPD(FEXCore::X86Tables::TYPE_GROUP_12, PF_NONE, 2), 1, &OpDispatchBuilder::PSRLI<2>},
     {OPD(FEXCore::X86Tables::TYPE_GROUP_12, PF_NONE, 4), 1, &OpDispatchBuilder::PSRAIOp<2>},
diff --git a/External/FEXCore/Source/Interface/Core/X86Tables/SecondaryGroupTables.cpp b/External/FEXCore/Source/Interface/Core/X86Tables/SecondaryGroupTables.cpp
index 393a268a5..f67b6e0ba 100644
--- a/External/FEXCore/Source/Interface/Core/X86Tables/SecondaryGroupTables.cpp
+++ b/External/FEXCore/Source/Interface/Core/X86Tables/SecondaryGroupTables.cpp
@@ -148,7 +148,7 @@ void InitializeSecondaryGroupTables() {
     // CMPXCHG8B/16B works with all prefixes
     // Tooling fails to decode CMPXCHG with prefix
     {OPD(TYPE_GROUP_9, PF_NONE, 0), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,   0, nullptr}},
-    {OPD(TYPE_GROUP_9, PF_NONE, 1), 1, X86InstInfo{"CMPXCHG8B",  TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
+    {OPD(TYPE_GROUP_9, PF_NONE, 1), 1, X86InstInfo{"CMPXCHG8B/16B", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_NONE, 2), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,   0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_NONE, 3), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,   0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_NONE, 4), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,   0, nullptr}},
@@ -157,7 +157,7 @@ void InitializeSecondaryGroupTables() {
     {OPD(TYPE_GROUP_9, PF_NONE, 7), 1, X86InstInfo{"RDSEED",     TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_REG_ONLY, 0, nullptr}},
 
     {OPD(TYPE_GROUP_9, PF_F3, 0), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
-    {OPD(TYPE_GROUP_9, PF_F3, 1), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
+    {OPD(TYPE_GROUP_9, PF_F3, 1), 1, X86InstInfo{"CMPXCHG8B/16B", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F3, 2), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F3, 3), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F3, 4), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
@@ -166,7 +166,7 @@ void InitializeSecondaryGroupTables() {
     {OPD(TYPE_GROUP_9, PF_F3, 7), 1, X86InstInfo{"RDPID",      TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
 
     {OPD(TYPE_GROUP_9, PF_66, 0), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
-    {OPD(TYPE_GROUP_9, PF_66, 1), 1, X86InstInfo{"CMPXCHG16B", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
+    {OPD(TYPE_GROUP_9, PF_66, 1), 1, X86InstInfo{"CMPXCHG8B/16B", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_66, 2), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_66, 3), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_66, 4), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
@@ -175,7 +175,7 @@ void InitializeSecondaryGroupTables() {
     {OPD(TYPE_GROUP_9, PF_66, 7), 1, X86InstInfo{"RDSEED",     TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_REG_ONLY, 0, nullptr}},
 
     {OPD(TYPE_GROUP_9, PF_F2, 0), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
-    {OPD(TYPE_GROUP_9, PF_F2, 1), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
+    {OPD(TYPE_GROUP_9, PF_F2, 1), 1, X86InstInfo{"CMPXCHG8B/16B", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST | FLAGS_SF_MOD_MEM_ONLY, 0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F2, 2), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F2, 3), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},
     {OPD(TYPE_GROUP_9, PF_F2, 4), 1, X86InstInfo{"",           TYPE_INVALID, FLAGS_NONE,     0, nullptr}},