Последняя бета-версия Stream SDK поддерживает OpenCL для GPU. Вот, собственно, весь список нововведений:

• First beta release of ATI Stream SDK with OpenCL GPU support.
• ATI Stream SDK v2.0 OpenCL is certified OpenCL 1.0 conformant by Khronos1.
• Added Microsoft Windows 7 support.
• Added native Microsoft Windows 64-bit support.
• Float comparisons in kernels no longer produce a runtime error.
• Various other issues from previous v2.0 beta releases have been resolved.

Берут тут: AMD Stream SDK 2.0 beta