I made a benchmark on my OpenCL application on i7-4771 and Xeon E5-2643 machine and the result is shocking me. E5-2643 spent much longer time to complete the test than i7-4771. I guess OpenCL uses both CPU and HD graphics GPU on i7-4771, but OpenCL can only use CPU on E5-2643 since it doesn't have HD graphics integrated.
I am not sure my guess is correct. So I am seeking answers here.
Thanks a lot!!