10 Replies Latest reply on Sep 4, 2012 12:06 PM by dmeiser

    Strange global memory bandwidth for HD 7970

    cadorino

      Hi to all,

      I run the GlobalMemoryBandwidth sample on a AMD 7970 and the results is the following:

       

      Platform 0 : Advanced Micro Devices, Inc.

      Platform found : Advanced Micro Devices, Inc.

       

      Selected Platform Vendor : Advanced Micro Devices, Inc.

      Device 0 : Tahiti Device ID is 005EF838

      Build Options are : -D DATATYPE=float4 -D OFFSET=16384

       

      Global Memory Read

      AccessType      : single

      VectorElements  : 4

      Bandwidth       : 1672.16 GB/s

       

      Global Memory Read

      AccessType      : linear

      VectorElements  : 4

      Bandwidth       : 1756.49 GB/s

       

      Global Memory Read

      AccessType      : linear(uncached)

      VectorElements  : 4

      Bandwidth       : 220.769 GB/s

       

      Global Memory Write

      AccessType      : linear

      VectorElements  : 4

      Bandwidth       : 501.668 GB/s

       

      The question is: how can the linear read bandwidth be over 1 terabyte per second is the max theoretical bandwidth is about 260 GB/s?

      The question that naturally follows is: are global buffer reads cached?

       

      Thank you very much!