i just noticed that data transfer from device (simple global memory without texture cache) to host is 1.3 times faster than data transfer from host to device.
the transfer of 5,1 MB data from host to device (global memory) takes about 2,39 ms ~> 2,34 GB/sec.
the transfer of the same data size back from device (global memory) to host takes just about 1,81 ms ~> 3,10 GB/sec.
i wonder why is this so!?
thank you very much for all answeres!
ps: i used a geforce 480 gtx