The compressors available in the NVIDIA Texture Tools are not designed for real-time compression. If you need to compress textures in real-time, I'd recommend to look at the following sources:

J.M.P. van Waveren was the first one to describe a real-time DXT compressor. This compressor is part of the of real-time texture streaming pipeline used in some id Software games. He obtains the following results with his SSE2 optimized implementation:

The same algorithm described by Waveren can also be adapted easily to the GPU. This is what Simon Green did in this OpenGL SDK example. The performance on the GPU is much more impressive:

A later whitepaper by Waveren and Ignacio Castaño provides even higher results on the GPU:

Peter Uliciansky optimized Waveren's algorithm further and published his results in this thread: Extreme DXT Compression, New algorithm for real-time DXT compression.

These numbers are very impressive and start to get closer to the results of the GPU implementation. However, as pointed by Charles Bloom this implementation has some errors.

Moreover, the latest GPU implementation also offers higher performance.

• http://developer.download.nvidia.com/SDK/10/opengl/samples.html#compress_YCoCgDXT
• http://developer.download.nvidia.com/SDK/10/opengl/samples.html#compress_NormalDXT

Other links:

• https://mollyrocket.com/forums/viewtopic.php?t=392
• http://www.evl.uic.edu/cavern/fastdxt/