diff --git a/src/nvtt/cuda/CudaCompressDXT.cpp b/src/nvtt/cuda/CudaCompressDXT.cpp
index 9947ea0..5fc7f8c 100644
--- a/src/nvtt/cuda/CudaCompressDXT.cpp
+++ b/src/nvtt/cuda/CudaCompressDXT.cpp
@@ -48,7 +48,8 @@ using namespace nvtt;
 
 #if defined HAVE_CUDA
 
-#define MAX_BLOCKS 32768 // 49152, 65535
+#define MAX_BLOCKS 8192U // 32768, 65535
+
 
 extern "C" void setupCompressKernel(const float weights[3]);
 extern "C" void compressKernelDXT1(uint blockNum, uint * d_data, uint * d_result, uint * d_bitmaps);
@@ -79,12 +80,15 @@ static void convertToBlockLinear(const Image * image, uint * blockLinearImage)
 #endif
 
 
-CudaCompressor::CudaCompressor()
+CudaCompressor::CudaCompressor() : m_bitmapTable(NULL), m_data(NULL), m_result(NULL)
 {
 #if defined HAVE_CUDA
     // Allocate and upload bitmaps.
     cudaMalloc((void**) &m_bitmapTable, 992 * sizeof(uint));
-    cudaMemcpy(m_bitmapTable, s_bitmapTable, 992 * sizeof(uint), cudaMemcpyHostToDevice);
+	if (m_bitmapTable != NULL)
+	{
+		cudaMemcpy(m_bitmapTable, s_bitmapTable, 992 * sizeof(uint), cudaMemcpyHostToDevice);
+	}
 
 	// Allocate scratch buffers.
     cudaMalloc((void**) &m_data, MAX_BLOCKS * 64U);
@@ -102,7 +106,16 @@ CudaCompressor::~CudaCompressor()
 #endif
 }
 
-
+bool CudaCompressor::isValid() const
+{
+#if defined HAVE_CUDA
+	if (cudaGetLastError() != cudaSuccess)
+   	{
+		return false;
+	}
+#endif
+	return m_data != NULL && m_result != NULL && m_bitmapTable != NULL;
+}
 
 // @@ This code is very repetitive and needs to be cleaned up.
 
@@ -119,7 +132,7 @@ void CudaCompressor::compressDXT1(const Image * image, const OutputOptions::Priv
 
 	uint imageSize = w * h * 16 * sizeof(Color32);
     uint * blockLinearImage = (uint *) malloc(imageSize);
-	convertToBlockLinear(image, blockLinearImage);	// @@ Do this on the GPU!
+	convertToBlockLinear(image, blockLinearImage);	// @@ Do this in parallel with the GPU, or in the GPU!
 
 	const uint blockNum = w * h;
 	const uint compressedSize = blockNum * 8;
diff --git a/src/nvtt/cuda/CudaCompressDXT.h b/src/nvtt/cuda/CudaCompressDXT.h
index c98c4e4..8e67315 100644
--- a/src/nvtt/cuda/CudaCompressDXT.h
+++ b/src/nvtt/cuda/CudaCompressDXT.h
@@ -37,6 +37,8 @@ namespace nv
 		CudaCompressor();
 		~CudaCompressor();
 
+		bool isValid() const;
+
 		void compressDXT1(const Image * image, const nvtt::OutputOptions::Private & outputOptions, const nvtt::CompressionOptions::Private & compressionOptions);
 		void compressDXT3(const Image * image, const nvtt::OutputOptions::Private & outputOptions, const nvtt::CompressionOptions::Private & compressionOptions);
 		void compressDXT5(const Image * image, const nvtt::OutputOptions::Private & outputOptions, const nvtt::CompressionOptions::Private & compressionOptions);