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Journeyman III

OpenCL performance / temperature rising

Hello guys,

I have some doubts about OpenCL usage and temperature rising.

I have created an application to render some things using only directx and another application to evaluate some things using only OpenCL. After some tests, OpenCL application could not reach a high temperature like the DirectX application did. Video card usage is being reported as 100% on both applications.

  1. Are there hardware differences on the video card that explains it? For example, OpenCL compute units cannot cause a temperature rising similar to the DirectX rendering application due hardware details? Or can it be only because the OpenCL application is not heavy enough?
  2. Are OpenCL hardware parts made to avoid high temperature rising?
  3. If the problem is because the OpenCL is not heavy enough, which OpenCL operations/actions inside the kernel or even among host and device could be heavier to the video card. I already know work itens/work group should be parameterized in such a way to mantain the video card totally busy.

Thanks in advance.

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2 Replies

Re: OpenCL performance / temperature rising

Hi dmcavalcante As I understand OpenCL and directX are just APIs to utilize the same hardware for some rather different purposes. GPUs are primarily made for rendering purpose, so there maybe some parts which are exposed in Directx but not in OpenCL. But this certainly does not mean, that GPU will be underutilized from OpenCL. At the end, GPU has lots of Compute units and keeping them busy for long time, is not very easy always. You can try running MatrixMultiplication samples for large matices (eg. 4K X 4K)and run it for thousands of iterations. Also make sure you are not using CPU in between, which gives GPU some time to rest. It will be helpful if you can give details as to what OpenCL application and DirectX applications you used for the above behaviour. Also please mention your GPU, Driver, SDK and OS details.

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Re: OpenCL performance / temperature rising

well there is quite chunk of GPU dedicated to graphics rendering which are not exposed and used by OpenCL. if DirectX use them it will cause more power consumptions and higher temperature.

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