PassMark software has identified the root cause of unexpectedly reduced computing performance on NVIDIA's new generation GeForce RTX 5090, RTX 5080 and RTX 5070 Ti GPUs. The reason is that Nvidia quietly stopped supporting 32-bit OpenCL and CUDA in its "Blackwell" architecture, causing compatibility issues with existing benchmarking tools and applications.

The problem became apparent when PassMark's DirectCompute benchmark returned error code "CL_OUT_OF_RESOURCES(-5)" on RTX5000 series graphics cards.

Upon investigation, the developers confirmed that while the main application for the benchmark has been 64-bit for years, several compute sub-benchmarks still use 32-bit code that previously ran fine on RTX 4000 and earlier GPUs. Nvidia has not explicitly documented this architectural change, and Nvidia's developer website continues to show 32-bit code samples and documentation despite the removal of actual support.

As a result, applications built on traditional CUDA infrastructure (including technologies such as PhysX) will experience significant performance degradation as computing tasks will fall back to CPU processing instead of taking advantage of the parallel architecture of the GPU. While this fallback mechanism allows legacy applications to run on the RTX40 series and previous hardware, the RTX5000 series handles these tasks entirely through the CPU, resulting in significantly reduced performance.

PassMark is working to port the affected OpenCL code to 64-bit so that the computing capabilities of the new GPUs can be properly tested. However, they warn that many existing applications containing 32-bit OpenCL components may never run properly on RTX 5000 series graphics cards without modifying the source code.

The benchmark developer also noted that this change does not fully explain DirectX9's poor performance, suggesting that other architectural changes may affect the traditional rendering path.

PassMark updated its software today, but traditional benchmarks may still be affected. Below are older benchmarks run without the latest PassMark V11.1 build 1004 patch, showing the impact the latest generation products suffer without proper software support.