diff --git a/src/Common/EncryptionThreadPool.c b/src/Common/EncryptionThreadPool.c
index 0dbaec5b..10052796 100644
--- a/src/Common/EncryptionThreadPool.c
+++ b/src/Common/EncryptionThreadPool.c
@@ -20,6 +20,12 @@
 #define TC_ENC_THREAD_POOL_MAX_THREAD_COUNT 256 //64
 #define TC_ENC_THREAD_POOL_QUEUE_SIZE (TC_ENC_THREAD_POOL_MAX_THREAD_COUNT * 2)
 
+#define TC_ENC_THREAD_POOL_LEGACY_MAX_THREAD_COUNT 64
+#define TC_ENC_THREAD_POOL_LEGACY_QUEUE_SIZE (TC_ENC_THREAD_POOL_LEGACY_MAX_THREAD_COUNT * 2)
+
+static volatile size_t ThreadPoolCount = TC_ENC_THREAD_POOL_LEGACY_MAX_THREAD_COUNT;
+static volatile int ThreadQueueSize = TC_ENC_THREAD_POOL_LEGACY_QUEUE_SIZE;
+
 #ifdef DEVICE_DRIVER
 
 #define TC_THREAD_HANDLE PKTHREAD
@@ -178,19 +184,22 @@ static void SetWorkItemState (EncryptionThreadPoolWorkItem *workItem, WorkItemSt
 static TC_THREAD_PROC EncryptionThreadProc (void *threadArg)
 {
 	EncryptionThreadPoolWorkItem *workItem;
-#ifdef DEVICE_DRIVER
-	SetThreadCpuGroupAffinity ((USHORT) *(WORD*)(threadArg));
-#else
-	SetThreadGroupAffinityFn SetThreadGroupAffinityPtr = (SetThreadGroupAffinityFn) GetProcAddress (GetModuleHandle (L"kernel32.dll"), "SetThreadGroupAffinity");
-	if (SetThreadGroupAffinityPtr && threadArg)
+	if (threadArg)
 	{
-		GROUP_AFFINITY groupAffinity = {0};
-		groupAffinity.Mask = ~0ULL;
-		groupAffinity.Group = *(WORD*)(threadArg);
-		SetThreadGroupAffinityPtr(GetCurrentThread(), &groupAffinity, NULL);
-	}
+#ifdef DEVICE_DRIVER
+		SetThreadCpuGroupAffinity ((USHORT) *(WORD*)(threadArg));
+#else
+		SetThreadGroupAffinityFn SetThreadGroupAffinityPtr = (SetThreadGroupAffinityFn) GetProcAddress (GetModuleHandle (L"kernel32.dll"), "SetThreadGroupAffinity");
+		if (SetThreadGroupAffinityPtr && threadArg)
+		{
+			GROUP_AFFINITY groupAffinity = {0};
+			groupAffinity.Mask = ~0ULL;
+			groupAffinity.Group = *(WORD*)(threadArg);
+			SetThreadGroupAffinityPtr(GetCurrentThread(), &groupAffinity, NULL);
+		}
 	
 #endif
+	}
 
 
 	while (!StopPending)
@@ -199,7 +208,7 @@ static TC_THREAD_PROC EncryptionThreadProc (void *threadArg)
 
 		workItem = &WorkItemQueue[DequeuePosition++];
 
-		if (DequeuePosition >= TC_ENC_THREAD_POOL_QUEUE_SIZE)
+		if (DequeuePosition >= ThreadQueueSize)
 			DequeuePosition = 0;
 
 		while (!StopPending && GetWorkItemState (workItem) != WorkItemReady)
@@ -288,13 +297,11 @@ static TC_THREAD_PROC EncryptionThreadProc (void *threadArg)
 #endif
 }
 
+#ifndef DEVICE_DRIVER
 
-BOOL EncryptionThreadPoolStart (size_t encryptionFreeCpuCount)
+size_t GetCpuCount (WORD* pGroupCount)
 {
-	size_t cpuCount = 0, i = 0;
-#ifdef DEVICE_DRIVER
-	cpuCount = GetCpuCount();
-#else
+	size_t cpuCount = 0;
 	SYSTEM_INFO sysInfo;
 	GetActiveProcessorGroupCountFn GetActiveProcessorGroupCountPtr = (GetActiveProcessorGroupCountFn) GetProcAddress (GetModuleHandle (L"Kernel32.dll"), "GetActiveProcessorGroupCount");
 	GetActiveProcessorCountFn GetActiveProcessorCountPtr = (GetActiveProcessorCountFn) GetProcAddress (GetModuleHandle (L"Kernel32.dll"), "GetActiveProcessorCount");
@@ -307,25 +314,47 @@ BOOL EncryptionThreadPoolStart (size_t encryptionFreeCpuCount)
 			totalProcessors += (size_t) GetActiveProcessorCountPtr(j);
 		}
 		cpuCount = totalProcessors;
+		if (pGroupCount)
+			*pGroupCount = groupCount;
 	}
 	else
 	{
 		GetSystemInfo(&sysInfo);
-		cpuCount = sysInfo.dwNumberOfProcessors;
+		cpuCount = (size_t) sysInfo.dwNumberOfProcessors;
+		if (pGroupCount)
+			*pGroupCount = 1;
 	}
+
+	return cpuCount;
+}
+
 #endif
 
+
+BOOL EncryptionThreadPoolStart (size_t encryptionFreeCpuCount)
+{
+	size_t cpuCount = 0, i = 0;
+	WORD groupCount = 1;
+
+	cpuCount = GetCpuCount(&groupCount);
+
 	if (ThreadPoolRunning)
 		return TRUE;
 
+	if (groupCount > 1)
+	{
+		ThreadPoolCount = TC_ENC_THREAD_POOL_MAX_THREAD_COUNT;
+		ThreadQueueSize = TC_ENC_THREAD_POOL_QUEUE_SIZE;
+	}
+
 	if (cpuCount > encryptionFreeCpuCount)
 		cpuCount -= encryptionFreeCpuCount;
 
 	if (cpuCount < 2)
 		return TRUE;
 
-	if (cpuCount > TC_ENC_THREAD_POOL_MAX_THREAD_COUNT)
-		cpuCount = TC_ENC_THREAD_POOL_MAX_THREAD_COUNT;
+	if (cpuCount > ThreadPoolCount)
+		cpuCount = ThreadPoolCount;
 
 	StopPending = FALSE;
 	DequeuePosition = 0;
@@ -377,32 +406,38 @@ BOOL EncryptionThreadPoolStart (size_t encryptionFreeCpuCount)
 
 	for (ThreadCount = 0; ThreadCount < cpuCount; ++ThreadCount)
 	{
-#ifdef DEVICE_DRIVER
-		ThreadProcessorGroups[ThreadCount] = GetCpuGroup ((size_t) ThreadCount);
-#else
-		// Determine which processor group to bind the thread to.
-		if (GetActiveProcessorGroupCountPtr && GetActiveProcessorCountPtr)
+		WORD* pThreadArg = NULL;
+		if (groupCount > 1)
 		{
-			WORD j, groupCount = GetActiveProcessorGroupCountPtr();
-			uint32 totalProcessors = 0U;
-			for (j = 0U; j < groupCount; j++)
+#ifdef DEVICE_DRIVER
+			ThreadProcessorGroups[ThreadCount] = GetCpuGroup ((size_t) ThreadCount);
+#else
+			GetActiveProcessorCountFn GetActiveProcessorCountPtr = (GetActiveProcessorCountFn) GetProcAddress (GetModuleHandle (L"Kernel32.dll"), "GetActiveProcessorCount");
+			// Determine which processor group to bind the thread to.
+			if (GetActiveProcessorCountPtr)
 			{
-				totalProcessors += (uint32) GetActiveProcessorCountPtr(j);
-				if (totalProcessors >= ThreadCount)
+				WORD j;
+				uint32 totalProcessors = 0U;
+				for (j = 0U; j < groupCount; j++)
 				{
-					ThreadProcessorGroups[ThreadCount] = j;
-					break;
+					totalProcessors += (uint32) GetActiveProcessorCountPtr(j);
+					if (totalProcessors >= ThreadCount)
+					{
+						ThreadProcessorGroups[ThreadCount] = j;
+						break;
+					}
 				}
 			}
-		}
-		else
-			ThreadProcessorGroups[ThreadCount] = 0;
+			else
+				ThreadProcessorGroups[ThreadCount] = 0;
 #endif
+			pThreadArg = &ThreadProcessorGroups[ThreadCount];
+		}
 
 #ifdef DEVICE_DRIVER
-		if (!NT_SUCCESS(TCStartThread(EncryptionThreadProc, (void*)(&ThreadProcessorGroups[ThreadCount]), &ThreadHandles[ThreadCount])))
+		if (!NT_SUCCESS(TCStartThread(EncryptionThreadProc, (void*) pThreadArg, &ThreadHandles[ThreadCount])))
 #else
-		if (!(ThreadHandles[ThreadCount] = (HANDLE)_beginthreadex(NULL, 0, EncryptionThreadProc, (void*)(&ThreadProcessorGroups[ThreadCount]), 0, NULL)))
+		if (!(ThreadHandles[ThreadCount] = (HANDLE)_beginthreadex(NULL, 0, EncryptionThreadProc, (void*) pThreadArg, 0, NULL)))
 #endif
 
 		{
@@ -465,7 +500,7 @@ void EncryptionThreadPoolBeginKeyDerivation (TC_EVENT *completionEvent, TC_EVENT
 	TC_ACQUIRE_MUTEX (&EnqueueMutex);
 
 	workItem = &WorkItemQueue[EnqueuePosition++];
-	if (EnqueuePosition >= TC_ENC_THREAD_POOL_QUEUE_SIZE)
+	if (EnqueuePosition >= ThreadQueueSize)
 		EnqueuePosition = 0;
 
 	while (GetWorkItemState (workItem) != WorkItemFree)
@@ -564,7 +599,7 @@ void EncryptionThreadPoolDoWork (EncryptionThreadPoolWorkType type, byte *data,
 	while (fragmentCount-- > 0)
 	{
 		workItem = &WorkItemQueue[EnqueuePosition++];
-		if (EnqueuePosition >= TC_ENC_THREAD_POOL_QUEUE_SIZE)
+		if (EnqueuePosition >= ThreadQueueSize)
 			EnqueuePosition = 0;
 
 		while (GetWorkItemState (workItem) != WorkItemFree)
@@ -606,7 +641,7 @@ size_t GetEncryptionThreadCount ()
 
 size_t GetMaxEncryptionThreadCount ()
 {
-	return TC_ENC_THREAD_POOL_MAX_THREAD_COUNT;
+	return ThreadPoolCount;
 }
 
 
diff --git a/src/Common/EncryptionThreadPool.h b/src/Common/EncryptionThreadPool.h
index 6a280621..161fb7ce 100644
--- a/src/Common/EncryptionThreadPool.h
+++ b/src/Common/EncryptionThreadPool.h
@@ -27,6 +27,10 @@ typedef enum
 	DeriveKeyWork
 } EncryptionThreadPoolWorkType;
 
+#ifndef DEVICE_DRIVER
+size_t GetCpuCount (WORD* pGroupCount);
+#endif
+
 void EncryptionThreadPoolBeginKeyDerivation (TC_EVENT *completionEvent, TC_EVENT *noOutstandingWorkItemEvent, LONG *completionFlag, LONG *outstandingWorkItemCount, int pkcs5Prf, char *password, int passwordLength, char *salt, int iterationCount, char *derivedKey);
 void EncryptionThreadPoolDoWork (EncryptionThreadPoolWorkType type, byte *data, const UINT64_STRUCT *startUnitNo, uint32 unitCount, PCRYPTO_INFO cryptoInfo);
 BOOL EncryptionThreadPoolStart (size_t encryptionFreeCpuCount);
diff --git a/src/Driver/Ntdriver.c b/src/Driver/Ntdriver.c
index 188c6647..957853cd 100644
--- a/src/Driver/Ntdriver.c
+++ b/src/Driver/Ntdriver.c
@@ -4491,7 +4491,7 @@ NTSTATUS TCCompleteDiskIrp (PIRP irp, NTSTATUS status, ULONG_PTR information)
 }
 
 
-size_t GetCpuCount ()
+size_t GetCpuCount (WORD* pGroupCount)
 {
 	size_t cpuCount = 0;
 	if (KeQueryActiveGroupCountPtr && KeQueryActiveProcessorCountExPtr)
@@ -4501,6 +4501,9 @@ size_t GetCpuCount ()
 		{
 			cpuCount += (size_t) KeQueryActiveProcessorCountExPtr (i);
 		}
+
+		if (pGroupCount)
+			*pGroupCount = groupCount;
 	}
 	else
 	{
@@ -4514,6 +4517,9 @@ size_t GetCpuCount ()
 
 			activeCpuMap >>= 1;
 		}
+
+		if (pGroupCount)
+			*pGroupCount = 1;
 	}
 
 	if (cpuCount == 0)
diff --git a/src/Driver/Ntdriver.h b/src/Driver/Ntdriver.h
index 25ee64e9..47ae49f7 100644
--- a/src/Driver/Ntdriver.h
+++ b/src/Driver/Ntdriver.h
@@ -173,7 +173,7 @@ NTSTATUS TCCompleteIrp (PIRP irp, NTSTATUS status, ULONG_PTR information);
 NTSTATUS TCCompleteDiskIrp (PIRP irp, NTSTATUS status, ULONG_PTR information);
 NTSTATUS ProbeRealDriveSize (PDEVICE_OBJECT driveDeviceObject, LARGE_INTEGER *driveSize);
 BOOL UserCanAccessDriveDevice ();
-size_t GetCpuCount ();
+size_t GetCpuCount (WORD* pGroupCount);
 USHORT GetCpuGroup (size_t index);
 void SetThreadCpuGroupAffinity (USHORT index);
 void EnsureNullTerminatedString (wchar_t *str, size_t maxSizeInBytes);