PCIe bandwidth test, which is correct?m

Discussion created by rollyng on Mar 27, 2011
Latest reply on Mar 30, 2011 by 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!