Jon Peddie Research analyst Alex Herrera claims the new x86 cross-compiler for NVIDIA's CUDA will hardly make the life of software developers much easier, because the performance on x86 processors will hardly be optimal.
Just like GPU-based Nvidia's PhysX tools that rely on CUDA do not support SIMD extensions like SSE2, the new compiler may not support things like AVX found in AMD Bulldozer and Intel Sandy Bridge microprocessors. As a result, the application will not run with maximum possible performance on x86 platforms.
"CUDA on x86 is going to be slower than an application optimized to run on x86 without CUDA, probably a lot slower. So a developer running a CUDA application on x86 and then on Fermi is going to see a larger speed-up than he might otherwise have had had he first optimized on a conventional, non-CUDA x86 platform. Bigger speedup numbers serve Nvidia’s purposes of showcasing how much faster GPUs are than CPUs on many floating-point intensive applications," said the analyst.