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[rollyng]

OpenCL PCIeBandwidth vs PCIeSpeedTest

Hi, I am running both tests on HD6970, WinXP x64,  CCC 11.2, SDK2.3. I have searched the forum and found there are discussions on this issue too.

With OpenCL PCIeBandwidth test, the Host to device: 0.286868 GB/s, Device to host: 1.65559 GB/s, both are very slow!

With PCIeSpeedTest_v0.2, CPU->GPU Bandwidth is 5.304 GB/s, GPU->CPU Bandwidth is 5.913 GB/s, both for 536MB data.

What is the reason for such big different btw the two tests? Becasue of data size? Can any one give a hint? Thank you!

[nou]

i have no such problem.Radeon 5850, Ubuntu 10.04 Catalyst 10.1, SDK 2.3

CAL - 5.825 GB/sec/6.671 GB/sec
OpenCL - 4.43402 GB/s 5.52109 GB/s

but in rpevious version of SDK i had similiar speed in OpenCL. so in next release it will be better.

[rollyng]

Hi nou, thanks for your info. Is this true because I am running Windows? Has anyone verified the performance with catalyst 11.2, SDK 2.3 on linux x64? Thanks!

[HarryH]

My results: 11.2, sdk2.3, x86_64, 5870

PCIeBandwidth:

Platform Vendor : Advanced Micro Devices, Inc.
Device 0 : Cypress
Host to device : 4.63619 GB/s
Device to host : 5.61816 GB/s

PCIeSpeedTest:

Peak CPU->GPU Bandwidth =   5.825 GB/sec [data size = 524288 bytes]
Peak GPU->CPU Bandwidth =   6.673 GB/sec [data size = 268435456 bytes]

[rollyng]

Hi Harry,

Thanks for the information, I shall test again on ubuntu 10.04 while I get my spare harddrive.