diff --git a/MCInst.c b/MCInst.c
index d0bdc68e..7b97ed00 100644
--- a/MCInst.c
+++ b/MCInst.c
@@ -17,12 +17,17 @@
 
 void MCInst_Init(MCInst *inst)
 {
+#if 0
+	// this loop consumes 2% of the whole disasm work
 	unsigned int i;
-
 	for (i = 0; i < 48; i++) {
 		inst->Operands[i].Kind = kInvalid;
 		inst->Operands[i].ImmVal = 0;
 	}
+#endif
+	// unnecessary to initialize in loop . its expensive and inst->size shuold be honored
+	inst->Operands[0].Kind = kInvalid;
+	inst->Operands[0].ImmVal = 0;
 
 	inst->Opcode = 0;
 	inst->OpcodePub = 0;
diff --git a/arch/X86/X86DisassemblerDecoder.c b/arch/X86/X86DisassemblerDecoder.c
index 35d93046..22acab36 100644
--- a/arch/X86/X86DisassemblerDecoder.c
+++ b/arch/X86/X86DisassemblerDecoder.c
@@ -1147,13 +1147,13 @@ static int getID(struct InternalInstruction *insn)
 		}
 	}
 
-	if (getIDWithAttrMask(&instructionID, insn, attrMask)) {
-		return -1;
-	}
-
 	/* The following clauses compensate for limitations of the tables. */
 	if (insn->mode != MODE_64BIT &&
 			insn->vectorExtensionType != TYPE_NO_VEX_XOP) {
+		if (getIDWithAttrMask(&instructionID, insn, attrMask)) {
+			return -1;
+		}
+
 		/*
 		 * The tables can't distinquish between cases where the W-bit is used to
 		 * select register size and cases where its a required part of the opcode.
@@ -1218,6 +1218,9 @@ static int getID(struct InternalInstruction *insn)
 
 		return 0;
 	}
+	if (getIDWithAttrMask(&instructionID, insn, attrMask)) {
+		return -1;
+	}
 
 	if ((insn->mode == MODE_16BIT || insn->hasOpSize) &&
 			!(attrMask & ATTR_OPSIZE)) {
@@ -1438,15 +1441,15 @@ static int readModRM(struct InternalInstruction* insn)
 	if (insn->consumedModRM)
 		return 0;
 
-    insn->modRMOffset = (uint8_t)(insn->readerCursor - insn->startLocation);
+	insn->modRMOffset = (uint8_t)(insn->readerCursor - insn->startLocation);
 
 	if (consumeByte(insn, &insn->modRM))
 		return -1;
 
 	insn->consumedModRM = true;
 
-    // save original ModRM for later reference
-    insn->orgModRM = insn->modRM;
+	// save original ModRM for later reference
+	insn->orgModRM = insn->modRM;
 
 	// handle MOVcr, MOVdr, MOVrc, MOVrd by pretending they have MRM.mod = 3
 	if ((insn->firstByte == 0x0f && insn->opcodeType == TWOBYTE) &&
diff --git a/cs.c b/cs.c
index e1669523..f67ddcb5 100644
--- a/cs.c
+++ b/cs.c
@@ -554,6 +554,15 @@ static void fill_insn(struct cs_struct *handle, cs_insn *insn, char *buffer, MCI
 		postprinter((csh)handle, insn, buffer, mci);
 
 #ifndef CAPSTONE_DIET
+	char *tab = strchr (buffer, '\t');
+	if (tab) {
+		*tab = 0;
+	}
+	strncpy (insn->mnemonic, buffer, sizeof (insn->mnemonic) - 1);
+	if (tab) {
+		strcpy (insn->op_str, tab + 1);
+	}
+#if 0
 	// fill in mnemonic & operands
 	// find first space or tab
 	mnem = insn->mnemonic;
@@ -568,6 +577,7 @@ static void fill_insn(struct cs_struct *handle, cs_insn *insn, char *buffer, MCI
 	}
 
 	*mnem = '\0';
+#endif
 
 	// we might have customized mnemonic
 	if (handle->mnem_list) {
@@ -588,6 +598,7 @@ static void fill_insn(struct cs_struct *handle, cs_insn *insn, char *buffer, MCI
 		}
 	}
 
+#if 0
 	// copy @op_str
 	if (*sp) {
 		// find the next non-space char
@@ -598,6 +609,7 @@ static void fill_insn(struct cs_struct *handle, cs_insn *insn, char *buffer, MCI
 	} else
 		insn->op_str[0] = '\0';
 #endif
+#endif
 }
 
 // how many bytes will we skip when encountering data (CS_OPT_SKIPDATA)?