# CPU \<--\> GPU is getting slow ?

**URL:** <https://forums.developer.nvidia.com/t/cpu-gpu-is-getting-slow/6236>\
**Category:** CUDA Programming and Performance\
**Created:** [November 6, 2008, 2:57am UTC](https://forums.developer.nvidia.com/t/cpu-gpu-is-getting-slow/6236 "2008-11-06T02:57:07Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Huang\_Wei\_Hao](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@Huang\_Wei\_Hao](https://forums.developer.nvidia.com/u/Huang_Wei_Hao)\
**Post date:** [November 6, 2008, 2:57am UTC](https://forums.developer.nvidia.com/t/cpu-gpu-is-getting-slow/6236/1 "2008-11-06T02:57:07Z")

</div>

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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