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    NUC6i7KyK GPU Degraded Performance for Microsoft AMP C++ Applications, with Graphics Drivers after 4501

    Jason2016

      The Intel Graphics Driver version effects the performance of compute limited applications on the NUC6i7KyK Skull Canyon NUCs.  All releases after 4501 (20.19.15.4501 of Intel Iris Pro Graphics 580) exhibit degraded performance when used with Microsoft AMP APIs - this is the same as Direct Compute.  The latest driver, released in Jan 2017 is verision 4590.  I have tested all drivers after 4501 and through 4590 and they all exhibit this slow down.

       

      I would guess that this degradation is caused by AMP APIs erroneously interpreting the GPU configuration of an Iris Pro 580 systems as if it was an Iris 540 system.  The Iris Pro 580s have 72 compute elements, whereas the Iris 540 systems have 48 compute elements.  The performance degradation is close to this 72:48 ratio (3:2).  For a benchmark I have developed on release 4501 I measure a compute time of about 2.7 seconds for a "standard unit of computation".  This same "standard unit of computation" requires about 4.1 seconds on driver releases after 4501 (note that 4.1 * 2 / 3 is approximately 2.7).

       

      A more public benchmark that exhibits the same issue is available here:

       

      [Updated 31 Jan 13] SystemCompute v0.5.7.2

       

      When running this benchmark and selecting option 2 (for Amp Tests instead of CPU tests), the results of the subtest in Stage 8, titled (AMPMatMul) exhibits this same type of slow down.  On My Skull Canyon it reports a value of 56 for driver version 4501.  On driver version 4590 the reported value is 74.  Attached are screen captures of these benchmark results.

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