diff --git a/benchmarks/accuracy_test.go b/benchmarks/accuracy_test.go
index 4e37ac9..a5d26be 100644
--- a/benchmarks/accuracy_test.go
+++ b/benchmarks/accuracy_test.go
@@ -137,6 +137,10 @@ func calculateError(simCPI, baselineCPI float64) float64 {
 // TestAccuracyAgainstBaseline compares simulator results against M2 baseline.
 // This is the main accuracy validation test for M2Sim.
 func TestAccuracyAgainstBaseline(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping long-running accuracy test in short mode")
+	}
+
 	// Load baseline data
 	baseline := loadBaseline(t)
 
@@ -212,6 +216,10 @@ func TestAccuracyAgainstBaseline(t *testing.T) {
 // TestAccuracyDependencyChain specifically tests the dependency chain accuracy.
 // This is critical because it measures the simulator's handling of RAW hazards.
 func TestAccuracyDependencyChain(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping accuracy test in short mode")
+	}
+
 	baseline := loadBaseline(t)
 	baselineEntry := findBaseline(baseline, "dependency")
 	if baselineEntry == nil {
@@ -249,6 +257,10 @@ func TestAccuracyDependencyChain(t *testing.T) {
 
 // TestAccuracyArithmetic tests ALU throughput accuracy.
 func TestAccuracyArithmetic(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping accuracy test in short mode")
+	}
+
 	baseline := loadBaseline(t)
 	baselineEntry := findBaseline(baseline, "arithmetic")
 	if baselineEntry == nil {
@@ -280,6 +292,10 @@ func TestAccuracyArithmetic(t *testing.T) {
 // TestAccuracyBranch tests branch handling accuracy using conditional branches.
 // Uses branchTakenConditional to match native benchmark pattern (CMP + B.GE).
 func TestAccuracyBranch(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping accuracy test in short mode")
+	}
+
 	baseline := loadBaseline(t)
 	baselineEntry := findBaseline(baseline, "branch")
 	if baselineEntry == nil {
@@ -373,6 +389,10 @@ func GenerateAccuracyReport(t *testing.T) AccuracyReport {
 
 // TestGenerateAccuracyReport tests the report generation and outputs JSON.
 func TestGenerateAccuracyReport(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping long-running accuracy report generation in short mode")
+	}
+
 	report := GenerateAccuracyReport(t)
 
 	reportJSON, err := json.MarshalIndent(report, "", "  ")
diff --git a/benchmarks/cpi_comparison_test.go b/benchmarks/cpi_comparison_test.go
index 386c366..ccbd443 100644
--- a/benchmarks/cpi_comparison_test.go
+++ b/benchmarks/cpi_comparison_test.go
@@ -52,6 +52,10 @@ func runFastTimingBenchmark(bench Benchmark) (cycles uint64, instructions uint64
 // that fast timing CPI approximations are reasonable relative to the detailed
 // pipeline model.
 func TestCPIComparison_FastVsFullPipeline(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping CPI comparison test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.EnableICache = false
@@ -137,6 +141,10 @@ func TestCPIComparison_FastVsFullPipeline(t *testing.T) {
 // TestCPIComparison_ThreeWay extends the comparison to include M2 hardware
 // baselines, providing a three-way view: hardware vs full pipeline vs fast timing.
 func TestCPIComparison_ThreeWay(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping three-way CPI comparison test in short mode")
+	}
+
 	// M2 hardware CPI baselines (from calibration_results.json, at 3.5 GHz)
 	// CPI = latency_ns * frequency_GHz
 	m2Baselines := map[string]float64{
diff --git a/benchmarks/dcache_accuracy_test.go b/benchmarks/dcache_accuracy_test.go
index b6e1b64..7fedcf1 100644
--- a/benchmarks/dcache_accuracy_test.go
+++ b/benchmarks/dcache_accuracy_test.go
@@ -11,6 +11,10 @@ import (
 // Output format: "    benchmark_name: CPI=X.XXX" matching the parser in
 // accuracy_report.py.
 func TestAccuracyCPI_WithDCache(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping D-cache accuracy test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.EnableICache = false
diff --git a/benchmarks/timing_harness_test.go b/benchmarks/timing_harness_test.go
index f3894d3..1be1df5 100644
--- a/benchmarks/timing_harness_test.go
+++ b/benchmarks/timing_harness_test.go
@@ -8,6 +8,10 @@ import (
 )
 
 func TestHarnessRunsAllBenchmarks(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping all benchmarks test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.Verbose = false
diff --git a/benchmarks/timing_validation_test.go b/benchmarks/timing_validation_test.go
index c391743..7c8d5cf 100644
--- a/benchmarks/timing_validation_test.go
+++ b/benchmarks/timing_validation_test.go
@@ -215,6 +215,10 @@ func TestTimingPredictions_FunctionCallOverhead(t *testing.T) {
 // TestTimingPredictions_CPIBounds validates that CPI is within reasonable bounds
 // for all benchmarks.
 func TestTimingPredictions_CPIBounds(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping CPI bounds test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.EnableICache = false
@@ -325,6 +329,10 @@ func TestTimingPredictions_CacheEffect(t *testing.T) {
 // TestTimingPredictions_StallAccounting validates that total stalls
 // equal the sum of stall types.
 func TestTimingPredictions_StallAccounting(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping stall accounting test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.EnableICache = false
@@ -355,6 +363,10 @@ func TestTimingPredictions_StallAccounting(t *testing.T) {
 // With 8-wide superscalar, we can retire up to 8 instructions per cycle,
 // so Cycles >= Instructions/8 (theoretically).
 func TestTimingPredictions_CycleEquation(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping cycle equation test in short mode")
+	}
+
 	config := DefaultConfig()
 	config.Output = &bytes.Buffer{}
 	config.EnableICache = false
diff --git a/emu/memory.go b/emu/memory.go
index 3943d6b..d4a21b3 100644
--- a/emu/memory.go
+++ b/emu/memory.go
@@ -3,33 +3,69 @@ package emu
 
 import "encoding/binary"
 
-// Memory provides a simple byte-addressable memory model for emulation.
+const (
+	// pageSize defines the size of each memory page (64KB)
+	pageSize = 64 * 1024
+	// pageMask is used to extract the page offset from an address
+	pageMask = pageSize - 1
+)
+
+// memoryPage represents a single page of memory
+type memoryPage struct {
+	data [pageSize]byte
+}
+
+// Memory provides a page-based byte-addressable memory model for emulation.
+// This optimization replaces the map[uint64]byte approach with a page-based system
+// to eliminate map access overhead, targeting the 3.95% CPU usage in Memory.Read32.
 type Memory struct {
-	data map[uint64]byte
+	pages map[uint64]*memoryPage
 }
 
 // NewMemory creates a new memory instance.
 func NewMemory() *Memory {
 	return &Memory{
-		data: make(map[uint64]byte),
+		pages: make(map[uint64]*memoryPage),
 	}
 }
 
+// getOrCreatePage gets an existing page or creates a new one for the given address.
+func (m *Memory) getOrCreatePage(addr uint64) *memoryPage {
+	pageAddr := addr &^ pageMask
+	page, exists := m.pages[pageAddr]
+	if !exists {
+		page = &memoryPage{}
+		m.pages[pageAddr] = page
+	}
+	return page
+}
+
+// getPage gets an existing page for the given address, or nil if it doesn't exist.
+func (m *Memory) getPage(addr uint64) *memoryPage {
+	pageAddr := addr &^ pageMask
+	return m.pages[pageAddr]
+}
+
 // Read8 reads a single byte from memory.
 func (m *Memory) Read8(addr uint64) byte {
-	return m.data[addr]
+	page := m.getPage(addr)
+	if page == nil {
+		return 0 // Return 0 for uninitialized memory
+	}
+	return page.data[addr&pageMask]
 }
 
 // Write8 writes a single byte to memory.
 func (m *Memory) Write8(addr uint64, value byte) {
-	m.data[addr] = value
+	page := m.getOrCreatePage(addr)
+	page.data[addr&pageMask] = value
 }
 
 // Read16 reads a 16-bit little-endian value from memory.
 func (m *Memory) Read16(addr uint64) uint16 {
 	var buf [2]byte
 	for i := uint64(0); i < 2; i++ {
-		buf[i] = m.data[addr+i]
+		buf[i] = m.Read8(addr + i)
 	}
 	return binary.LittleEndian.Uint16(buf[:])
 }
@@ -39,7 +75,7 @@ func (m *Memory) Write16(addr uint64, value uint16) {
 	var buf [2]byte
 	binary.LittleEndian.PutUint16(buf[:], value)
 	for i := uint64(0); i < 2; i++ {
-		m.data[addr+i] = buf[i]
+		m.Write8(addr+i, buf[i])
 	}
 }
 
@@ -47,7 +83,7 @@ func (m *Memory) Write16(addr uint64, value uint16) {
 func (m *Memory) Read32(addr uint64) uint32 {
 	var buf [4]byte
 	for i := uint64(0); i < 4; i++ {
-		buf[i] = m.data[addr+i]
+		buf[i] = m.Read8(addr + i)
 	}
 	return binary.LittleEndian.Uint32(buf[:])
 }
@@ -57,7 +93,7 @@ func (m *Memory) Write32(addr uint64, value uint32) {
 	var buf [4]byte
 	binary.LittleEndian.PutUint32(buf[:], value)
 	for i := uint64(0); i < 4; i++ {
-		m.data[addr+i] = buf[i]
+		m.Write8(addr+i, buf[i])
 	}
 }
 
@@ -65,7 +101,7 @@ func (m *Memory) Write32(addr uint64, value uint32) {
 func (m *Memory) Read64(addr uint64) uint64 {
 	var buf [8]byte
 	for i := uint64(0); i < 8; i++ {
-		buf[i] = m.data[addr+i]
+		buf[i] = m.Read8(addr + i)
 	}
 	return binary.LittleEndian.Uint64(buf[:])
 }
@@ -75,13 +111,13 @@ func (m *Memory) Write64(addr uint64, value uint64) {
 	var buf [8]byte
 	binary.LittleEndian.PutUint64(buf[:], value)
 	for i := uint64(0); i < 8; i++ {
-		m.data[addr+i] = buf[i]
+		m.Write8(addr+i, buf[i])
 	}
 }
 
 // LoadProgram loads a binary program into memory at the specified address.
 func (m *Memory) LoadProgram(addr uint64, program []byte) {
 	for i, b := range program {
-		m.data[addr+uint64(i)] = b
+		m.Write8(addr+uint64(i), b)
 	}
 }
diff --git a/timing/pipeline/stages.go b/timing/pipeline/stages.go
index 76b144d..3006177 100644
--- a/timing/pipeline/stages.go
+++ b/timing/pipeline/stages.go
@@ -30,14 +30,62 @@ type DecodeStage struct {
 	// Supports up to 8 concurrent decode operations (for 8-wide superscalar pipelines)
 	instPool [8]insts.Instruction
 	poolIndex int
+	// Pre-computed opcode lookup tables for O(1) instruction classification
+	// Eliminates switch statement overhead that causes map access patterns (9.29% CPU usage)
+	isLoadOpTable    [256]bool
+	isStoreOpTable   [256]bool
+	isRegWriteOpTable [256]bool
+	isBranchOpTable  [256]bool
 }
 
 // NewDecodeStage creates a new decode stage.
 func NewDecodeStage(regFile *emu.RegFile) *DecodeStage {
-	return &DecodeStage{
+	stage := &DecodeStage{
 		regFile: regFile,
 		decoder: insts.NewDecoder(),
 	}
+	stage.initOpcodeLookupTables()
+	return stage
+}
+
+// initOpcodeLookupTables initializes the pre-computed opcode classification tables.
+func (s *DecodeStage) initOpcodeLookupTables() {
+	// Initialize load operation lookup table
+	loadOps := []insts.Op{
+		insts.OpLDR, insts.OpLDP, insts.OpLDRB, insts.OpLDRSB,
+		insts.OpLDRH, insts.OpLDRSH, insts.OpLDRLit, insts.OpLDRQ,
+	}
+	for _, op := range loadOps {
+		s.isLoadOpTable[op] = true
+	}
+
+	// Initialize store operation lookup table
+	storeOps := []insts.Op{
+		insts.OpSTR, insts.OpSTP, insts.OpSTRB, insts.OpSTRH, insts.OpSTRQ,
+	}
+	for _, op := range storeOps {
+		s.isStoreOpTable[op] = true
+	}
+
+	// Initialize register write operation lookup table
+	regWriteOps := []insts.Op{
+		insts.OpADD, insts.OpSUB, insts.OpAND, insts.OpORR, insts.OpEOR,
+		insts.OpBIC, insts.OpORN, insts.OpEON,
+		insts.OpLDR, insts.OpLDP, insts.OpLDRB, insts.OpLDRSB,
+		insts.OpLDRH, insts.OpLDRSH, insts.OpLDRLit, insts.OpLDRQ,
+		insts.OpBL, insts.OpBLR,
+	}
+	for _, op := range regWriteOps {
+		s.isRegWriteOpTable[op] = true
+	}
+
+	// Initialize branch operation lookup table
+	branchOps := []insts.Op{
+		insts.OpB, insts.OpBL, insts.OpBCond, insts.OpBR, insts.OpBLR, insts.OpRET,
+	}
+	for _, op := range branchOps {
+		s.isBranchOpTable[op] = true
+	}
 }
 
 // DecodeResult contains the output of the decode stage.
@@ -94,23 +142,18 @@ func (s *DecodeStage) Decode(word uint32, pc uint64) DecodeResult {
 
 // isLoadOp returns true if the opcode is a load operation.
 func (s *DecodeStage) isLoadOp(op insts.Op) bool {
-	switch op {
-	case insts.OpLDR, insts.OpLDP, insts.OpLDRB, insts.OpLDRSB,
-		insts.OpLDRH, insts.OpLDRSH, insts.OpLDRLit, insts.OpLDRQ:
-		return true
-	default:
+	if int(op) >= len(s.isLoadOpTable) {
 		return false
 	}
+	return s.isLoadOpTable[op]
 }
 
 // isStoreOp returns true if the opcode is a store operation.
 func (s *DecodeStage) isStoreOp(op insts.Op) bool {
-	switch op {
-	case insts.OpSTR, insts.OpSTP, insts.OpSTRB, insts.OpSTRH, insts.OpSTRQ:
-		return true
-	default:
+	if int(op) >= len(s.isStoreOpTable) {
 		return false
 	}
+	return s.isStoreOpTable[op]
 }
 
 // isRegWriteInst determines if the instruction writes to a register.
@@ -120,28 +163,18 @@ func (s *DecodeStage) isRegWriteInst(inst *insts.Instruction) bool {
 		return false
 	}
 
-	switch inst.Op {
-	case insts.OpADD, insts.OpSUB, insts.OpAND, insts.OpORR, insts.OpEOR,
-		insts.OpBIC, insts.OpORN, insts.OpEON:
-		return true
-	case insts.OpLDR, insts.OpLDP, insts.OpLDRB, insts.OpLDRSB,
-		insts.OpLDRH, insts.OpLDRSH, insts.OpLDRLit, insts.OpLDRQ:
-		return true
-	case insts.OpBL, insts.OpBLR:
-		return true // BL/BLR write to X30
-	default:
+	if int(inst.Op) >= len(s.isRegWriteOpTable) {
 		return false
 	}
+	return s.isRegWriteOpTable[inst.Op]
 }
 
 // isBranchInst determines if the instruction is a branch.
 func (s *DecodeStage) isBranchInst(inst *insts.Instruction) bool {
-	switch inst.Op {
-	case insts.OpB, insts.OpBL, insts.OpBCond, insts.OpBR, insts.OpBLR, insts.OpRET:
-		return true
-	default:
+	if int(inst.Op) >= len(s.isBranchOpTable) {
 		return false
 	}
+	return s.isBranchOpTable[inst.Op]
 }
 
 // ExecuteStage performs ALU operations.