CPU <--> GPU is getting slow ?

I ran the CUDA project ~ bandwidthTest…
The result shows that Host -> Device Bandwidth is only 325.6 (MB/s)
Device -> Host Bandwidth is only 407.0 (MB/s)
The speed is too slow… :blink:
I remember that speed was over 2G/s before …
How can I solve this problem…

here is the test result …

Running on…
device 0:GeForce GTX 280
Quick Mode
Host to Device Bandwidth for Pageable memory
.
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 325.6

Quick Mode
Device to Host Bandwidth for Pageable memory
.
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 407.0

Quick Mode
Device to Device Bandwidth
.
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 114879.8

&&&& Test PASSED

Press ENTER to exit…

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