8 Replies Latest reply on Jul 14, 2015 11:12 AM by mz24cn

    Why Hawaii/Spectre (R9 290X/A10-7870K R7) slower five ~ ten times than Intel/NVidia on atomic adding operations?

    mz24cn

      The code VS2013 project is attahced.

      AMD driver version is 15.2 WHQL (OpenCL 2.0/1.2 1800.3).

       

      The results are as below:

      //NUM_PARALLEL = 1024;
      Platform: AMD Accelerated Parallel Processing
      Hawaii
      27382 microseconds.
      858994483       858996531       5120    7168
      Spectre
      25421 microseconds.
      858994483       858996531       5120    7168
      Cypress
      24200 microseconds.
      858994483       858996531       5120    7168

      //NUM_PARALLEL = 1024000000;
      Platform: AMD Accelerated Parallel Processing
      Hawaii
      7784847 microseconds.
      1882993459      3930993459      825032704       2873032704
      Spectre
      64862811 microseconds.
      1882993459      3930993459      825032704       2873032704
      Cypress
      144374737 microseconds.
      1882993459      3930993459      825032704       2873032704

       

      //NUM_PARALLEL = 1024;
      Platform: NVIDIA CUDA
      GeForce GTX 850M
      2006 microseconds.
      858994483       858996531       5120    7168

      Platform: Intel(R) OpenCL
      Intel(R) HD Graphics 4600
      3788 microseconds.
      858994483       858996531       5120    7168

      //NUM_PARALLEL = 1024000000;
      Platform: NVIDIA CUDA
      GeForce GTX 850M
      568615 microseconds.
      1882993459      3930993459      825032704       2873032704

      Platform: Intel(R) OpenCL
      Intel(R) HD Graphics 4600
      12791289 microseconds.
      1882993459      3930993459      825032704       2873032704

       

      GTX 850M only has 640 shaders while Hawaii has 2816.