GPU (AMD vs NVIDIA) seems to impact CPU performance #56393

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opened 2018-08-14 22:18:53 +02:00 by William George · 4 comments

On a single platform / CPU (AMD X399 + Threadripper 2990WX) the CPU performance result in the Blender Benchmark is 2 to 7% faster with a GeForce GTX 1080 Ti video card installed than with a Radeon RX Vega 64. The GPU results should be different, of course, but I am surprised that the GPU is affecting the CPU's performance. The only difference is the video card itself, and of course the accompanying drivers. OS is Windows 10 version 1803. Here are the results files from both test runs:

AMD Radeon RX Vega 64:

{

"blender_version": {
  "build_commit_date": "2018-03-22",
  "build_commit_time": "14:10",
  "build_date": "2018-03-22",
  "build_hash": "f4dc9f9d68b",
  "build_time": "09:59 AM",
  "version": "2.79 (sub 0)"
},
"device_info": {
  "compute_devices": [
    "AMD Ryzen Threadripper 2990WX 32-Core Processor"
  ],
  "device_type": "CPU",
  "num_cpu_threads": 64
},
"scenes": [
  {
    "name": "barbershop_interior",
    "stats": {
      "device_memory_usage": 2345.85,
      "device_peak_memory": 2345.85,
      "pipeline_render_time": 544.51,
      "render_time_no_sync": 497.189,
      "result": "OK",
      "total_render_time": 543.668
    }
  },
  {
    "name": "bmw27",
    "stats": {
      "device_memory_usage": 141.18,
      "device_peak_memory": 141.18,
      "pipeline_render_time": 97.42,
      "render_time_no_sync": 94.332,
      "result": "OK",
      "total_render_time": 96.2526
    }
  },
  {
    "name": "classroom",
    "stats": {
      "device_memory_usage": 298.97,
      "device_peak_memory": 298.97,
      "pipeline_render_time": 320.57,
      "render_time_no_sync": 317.105,
      "result": "OK",
      "total_render_time": 319.762
    }
  },
  {
    "name": "fishy_cat",
    "stats": {
      "device_memory_usage": 465.92,
      "device_peak_memory": 465.92,
      "pipeline_render_time": 146.24,
      "render_time_no_sync": 137.842,
      "result": "OK",
      "total_render_time": 145.291
    }
  },
  {
    "name": "koro",
    "stats": {
      "device_memory_usage": 450.31,
      "device_peak_memory": 450.31,
      "pipeline_render_time": 208.55,
      "render_time_no_sync": 198.978,
      "result": "OK",
      "total_render_time": 208.222
    }
  },
  {
    "name": "pavillon_barcelona",
    "stats": {
      "device_memory_usage": 151.27,
      "device_peak_memory": 151.27,
      "pipeline_render_time": 236.85,
      "render_time_no_sync": 233.724,
      "result": "OK",
      "total_render_time": 234.889
    }
  }
],
"system_info": {
  "bitness": "64bit",
  "cpu_brand": "AMD Ryzen Threadripper 2990WX 32-Core Processor",
  "devices": [
    {
      "name": "AMD Ryzen Threadripper 2990WX 32-Core Processor",
      "type": "CPU"
    },
    {
      "name": "Radeon RX Vega 64",
      "type": "OPENCL"
    }
  ],
  "machine": "AMD64",
  "num_cpu_cores": 32,
  "num_cpu_sockets": 1,
  "num_cpu_threads": 64,
  "system": "Windows"
},
"timestamp": "2018-08-14T17:50:22.782774+00:00"

}

GeForce GTX 1080 Ti:

{

"blender_version": {
  "build_commit_date": "2018-03-22",
  "build_commit_time": "14:10",
  "build_date": "2018-03-22",
  "build_hash": "f4dc9f9d68b",
  "build_time": "09:59 AM",
  "version": "2.79 (sub 0)"
},
"device_info": {
  "compute_devices": [
    "AMD Ryzen Threadripper 2990WX 32-Core Processor"
  ],
  "device_type": "CPU",
  "num_cpu_threads": 64
},
"scenes": [
  {
    "name": "barbershop_interior",
    "stats": {
      "device_memory_usage": 2345.85,
      "device_peak_memory": 2345.85,
      "pipeline_render_time": 525.09,
      "render_time_no_sync": 480.751,
      "result": "OK",
      "total_render_time": 524.274
    }
  },
  {
    "name": "bmw27",
    "stats": {
      "device_memory_usage": 141.18,
      "device_peak_memory": 141.18,
      "pipeline_render_time": 90.97,
      "render_time_no_sync": 87.9888,
      "result": "OK",
      "total_render_time": 89.829
    }
  },
  {
    "name": "classroom",
    "stats": {
      "device_memory_usage": 298.97,
      "device_peak_memory": 298.97,
      "pipeline_render_time": 302.82,
      "render_time_no_sync": 299.535,
      "result": "OK",
      "total_render_time": 302.044
    }
  },
  {
    "name": "fishy_cat",
    "stats": {
      "device_memory_usage": 465.92,
      "device_peak_memory": 465.92,
      "pipeline_render_time": 141.17000000000002,
      "render_time_no_sync": 132.919,
      "result": "OK",
      "total_render_time": 140.213
    }
  },
  {
    "name": "koro",
    "stats": {
      "device_memory_usage": 450.31,
      "device_peak_memory": 450.31,
      "pipeline_render_time": 202.62,
      "render_time_no_sync": 193.604,
      "result": "OK",
      "total_render_time": 202.318
    }
  },
  {
    "name": "pavillon_barcelona",
    "stats": {
      "device_memory_usage": 151.27,
      "device_peak_memory": 151.27,
      "pipeline_render_time": 231.29,
      "render_time_no_sync": 228.149,
      "result": "OK",
      "total_render_time": 229.373
    }
  }
],
"system_info": {
  "bitness": "64bit",
  "cpu_brand": "AMD Ryzen Threadripper 2990WX 32-Core Processor",
  "devices": [
    {
      "name": "AMD Ryzen Threadripper 2990WX 32-Core Processor",
      "type": "CPU"
    },
    {
      "name": "GeForce GTX 1080 Ti",
      "type": "CUDA"
    }
  ],
  "machine": "AMD64",
  "num_cpu_cores": 32,
  "num_cpu_sockets": 1,
  "num_cpu_threads": 64,
  "system": "Windows"
},
"timestamp": "2018-08-13T21:34:51.742436+00:00"

}

Time differences:

"barbershop_interior"
543.668 vs 524.274 = 3.7%

"bmw27"
96.2526 vs 89.829 = 7.2%

"classroom"
319.762 vs 302.044 = 5.9%

"fishy_cat"
145.291 vs 140.213 = 3.6%

"koro"
208.222 vs 202.318 = 2.9%

"pavillon_barcelona"
234.889 vs 229.373 = 2.4%

On a single platform / CPU (AMD X399 + Threadripper 2990WX) the CPU performance result in the Blender Benchmark is 2 to 7% faster with a GeForce GTX 1080 Ti video card installed than with a Radeon RX Vega 64. The GPU results should be different, of course, but I am surprised that the GPU is affecting the CPU's performance. The only difference is the video card itself, and of course the accompanying drivers. OS is Windows 10 version 1803. Here are the results files from both test runs: AMD Radeon RX Vega 64: { ``` "blender_version": { "build_commit_date": "2018-03-22", "build_commit_time": "14:10", "build_date": "2018-03-22", "build_hash": "f4dc9f9d68b", "build_time": "09:59 AM", "version": "2.79 (sub 0)" }, "device_info": { "compute_devices": [ "AMD Ryzen Threadripper 2990WX 32-Core Processor" ], "device_type": "CPU", "num_cpu_threads": 64 }, "scenes": [ { "name": "barbershop_interior", "stats": { "device_memory_usage": 2345.85, "device_peak_memory": 2345.85, "pipeline_render_time": 544.51, "render_time_no_sync": 497.189, "result": "OK", "total_render_time": 543.668 } }, { "name": "bmw27", "stats": { "device_memory_usage": 141.18, "device_peak_memory": 141.18, "pipeline_render_time": 97.42, "render_time_no_sync": 94.332, "result": "OK", "total_render_time": 96.2526 } }, { "name": "classroom", "stats": { "device_memory_usage": 298.97, "device_peak_memory": 298.97, "pipeline_render_time": 320.57, "render_time_no_sync": 317.105, "result": "OK", "total_render_time": 319.762 } }, { "name": "fishy_cat", "stats": { "device_memory_usage": 465.92, "device_peak_memory": 465.92, "pipeline_render_time": 146.24, "render_time_no_sync": 137.842, "result": "OK", "total_render_time": 145.291 } }, { "name": "koro", "stats": { "device_memory_usage": 450.31, "device_peak_memory": 450.31, "pipeline_render_time": 208.55, "render_time_no_sync": 198.978, "result": "OK", "total_render_time": 208.222 } }, { "name": "pavillon_barcelona", "stats": { "device_memory_usage": 151.27, "device_peak_memory": 151.27, "pipeline_render_time": 236.85, "render_time_no_sync": 233.724, "result": "OK", "total_render_time": 234.889 } } ], "system_info": { "bitness": "64bit", "cpu_brand": "AMD Ryzen Threadripper 2990WX 32-Core Processor", "devices": [ { "name": "AMD Ryzen Threadripper 2990WX 32-Core Processor", "type": "CPU" }, { "name": "Radeon RX Vega 64", "type": "OPENCL" } ], "machine": "AMD64", "num_cpu_cores": 32, "num_cpu_sockets": 1, "num_cpu_threads": 64, "system": "Windows" }, "timestamp": "2018-08-14T17:50:22.782774+00:00" ``` } GeForce GTX 1080 Ti: { ``` "blender_version": { "build_commit_date": "2018-03-22", "build_commit_time": "14:10", "build_date": "2018-03-22", "build_hash": "f4dc9f9d68b", "build_time": "09:59 AM", "version": "2.79 (sub 0)" }, "device_info": { "compute_devices": [ "AMD Ryzen Threadripper 2990WX 32-Core Processor" ], "device_type": "CPU", "num_cpu_threads": 64 }, "scenes": [ { "name": "barbershop_interior", "stats": { "device_memory_usage": 2345.85, "device_peak_memory": 2345.85, "pipeline_render_time": 525.09, "render_time_no_sync": 480.751, "result": "OK", "total_render_time": 524.274 } }, { "name": "bmw27", "stats": { "device_memory_usage": 141.18, "device_peak_memory": 141.18, "pipeline_render_time": 90.97, "render_time_no_sync": 87.9888, "result": "OK", "total_render_time": 89.829 } }, { "name": "classroom", "stats": { "device_memory_usage": 298.97, "device_peak_memory": 298.97, "pipeline_render_time": 302.82, "render_time_no_sync": 299.535, "result": "OK", "total_render_time": 302.044 } }, { "name": "fishy_cat", "stats": { "device_memory_usage": 465.92, "device_peak_memory": 465.92, "pipeline_render_time": 141.17000000000002, "render_time_no_sync": 132.919, "result": "OK", "total_render_time": 140.213 } }, { "name": "koro", "stats": { "device_memory_usage": 450.31, "device_peak_memory": 450.31, "pipeline_render_time": 202.62, "render_time_no_sync": 193.604, "result": "OK", "total_render_time": 202.318 } }, { "name": "pavillon_barcelona", "stats": { "device_memory_usage": 151.27, "device_peak_memory": 151.27, "pipeline_render_time": 231.29, "render_time_no_sync": 228.149, "result": "OK", "total_render_time": 229.373 } } ], "system_info": { "bitness": "64bit", "cpu_brand": "AMD Ryzen Threadripper 2990WX 32-Core Processor", "devices": [ { "name": "AMD Ryzen Threadripper 2990WX 32-Core Processor", "type": "CPU" }, { "name": "GeForce GTX 1080 Ti", "type": "CUDA" } ], "machine": "AMD64", "num_cpu_cores": 32, "num_cpu_sockets": 1, "num_cpu_threads": 64, "system": "Windows" }, "timestamp": "2018-08-13T21:34:51.742436+00:00" ``` } Time differences: "barbershop_interior" 543.668 vs 524.274 = 3.7% "bmw27" 96.2526 vs 89.829 = 7.2% "classroom" 319.762 vs 302.044 = 5.9% "fishy_cat" 145.291 vs 140.213 = 3.6% "koro" 208.222 vs 202.318 = 2.9% "pavillon_barcelona" 234.889 vs 229.373 = 2.4%
Author

Added subscriber: @PS-William

Added subscriber: @PS-William

Added subscriber: @brecht

Added subscriber: @brecht

Changed status from 'Open' to: 'Archived'

Changed status from 'Open' to: 'Archived'
Brecht Van Lommel self-assigned this 2018-08-15 11:35:22 +02:00

There's may be various reasons for this, but I doubt any of them is fixable in Blender.

  • Background tasks may have been running for on run but not the other.
  • CPU heating and throttling, differences in power supply with a different GPU.
  • Random scheduling to a less optimal core, or placement in a poor memory location due to ASLR.
  • General graphics driver overhead.

The Blender instance running the benchmark will not GPU when CPU rendering is set. To get closely repeatable results requires very careful system setup, 2-7% performance differences are well within the margin of error when not doing that I think.

There's may be various reasons for this, but I doubt any of them is fixable in Blender. * Background tasks may have been running for on run but not the other. * CPU heating and throttling, differences in power supply with a different GPU. * Random scheduling to a less optimal core, or placement in a poor memory location due to ASLR. * General graphics driver overhead. The Blender instance running the benchmark will not GPU when CPU rendering is set. To get closely repeatable results requires very careful system setup, 2-7% performance differences are well within the margin of error when not doing that I think.
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Reference: infrastructure/blender-open-data#56393
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