I have a real time application running on a GTX 8800. I am using the same GPU for visualization. I realized that CUDA is limited if the same card is used for graphics therefore I’m thinking about getting a new GPU. Do I have use SLI if I want to add another GPU? . i.e should I buy an identical card or I can use an older card that I have (6800 GT on another PCI exp)? PS my application is real time and I’m using the GlLmapbuffer right now. So I’m not sure how much the performance is going to increase if I use another GPU since I can’t use GlLmapbuffer anymore.
BTW when I tested the bandwidth of CUDA I found out that my bandwidth is too low. Is it because I’m running CUDA on the same card that I’m doing graphics?
Host to Device Bandwidth for Pageable memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 576.9
Device to Host Bandwidth for Pageable memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 807.1
Device to Device Bandwidth
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 71109.9
So I moved my GTX 8800 to another computer. Now I have a 6600 GT for visualization and my motherboard is an ASUS p5nd2-sli but now the results of my bandwidth test are worst!
Is there any manual for using another GPU with cuda? Now that I have another GPU, Do I need to change anything in the codes?
Here is my new bandwidth test results.
>bandwidthtest
Quick Mode
Host to Device Bandwidth for Pageable memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 184.8
Quick Mode
Device to Host Bandwidth for Pageable memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 201.8
Quick Mode
Device to Device Bandwidth
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 45942.6
>bandwidthTest --memory=pinned
Quick Mode
Host to Device Bandwidth for Pinned memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 186.3
Quick Mode
Device to Host Bandwidth for Pinned memory
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 205.0
Quick Mode
Device to Device Bandwidth
Transfer Size (Bytes) Bandwidth(MB/s)
33554432 69996.7
It’s very weird that your Device-to-Device performance went up with the pinned test, since pinned memory should have no impact on Device-to-Device copies.
Lacking any other good ideas: Are you sure both PCI-Express power connectors on your 8800 GTX are plugged in fully? I know the card will downclock itself if it isn’t getting enough power. What kind of power supply is in this system?
I have checked my card on two different computers and got these results. I’m pretty sure the power connections are fine. I also checked the voltage of the power; it is 11.98. Is there any software for testing the card?