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Tirael
BOHICA
Premium Member
join:2009-03-18
Sacramento, CA

Tirael to JoelC707

Premium Member

to JoelC707

Re: Do x16 video cards use that much bandwidth?

Click for full size
SS of GPUs
I decided to run the program to give you an idea of what it does. I also wanted to show you the difference between single vs SLI/crossfire GPU bandwidth. Above is a screenshot of PrecisionX so you can see the type (and number) of GPUs I have installed. Using two GTX 770 on the x79 platform (with PCI-E 3.0), this is what the program gives me:

System specifications
MSI XPOWER II Big Bang
Intel i7-3930k (PCI-E 3.0 enabled through registry)
Windows 8.1
GTX 770 SLI (PCI-E 3.0 x16)

E:\Downloads\EVGAPrecisionX15>concBandwidthTest.exe
usage: concBandwidthTest.exe deviceID deviceID...
 
##Test 1, using GPU 0 (GTX 770)
 
E:\Downloads\EVGAPrecisionX15>concBandwidthTest.exe 0
Device 0 took 588.792175 ms
Average HtoD bandwidth in MB/s: 10869.709668
Device 0 took 529.417114 ms
Average DtoH bandwidth in MB/s: 12088.766735
Device 0 took 1118.879761 ms
Average bidirectional bandwidth in MB/s: 11440.013886
 
## Test 2, using GPU 1 (GTX 770)
 
E:\Downloads\EVGAPrecisionX15>concBandwidthTest.exe 1
Device 1 took 579.526978 ms
Average HtoD bandwidth in MB/s: 11043.489342
Device 1 took 536.446045 ms
Average DtoH bandwidth in MB/s: 11930.370371
Device 1 took 1106.809448 ms
Average bidirectional bandwidth in MB/s: 11564.772979
 
## Test 3, using GPUs 0 and 1 (GTX 770 SLI)
 
E:\Downloads\EVGAPrecisionX15>concBandwidthTest.exe 0 1
Device 0 took 609.175659 ms
Device 1 took 605.729431 ms
Average HtoD bandwidth in MB/s: 21071.774408
Device 0 took 529.386719 ms
Device 1 took 529.211304 ms
Average DtoH bandwidth in MB/s: 24182.928893
Device 0 took 1136.735718 ms
Device 1 took 1134.876465 ms
Average bidirectional bandwidth in MB/s: 22539.073655
 

I ran the program with/without PCI-E 3.0 enabled. However, it requires a registry hack to do so on my CPU (since the i7-39xx series is 3.0 compliant, but does not have the 3.0 certification), so I do not want to be constantly restarting my computer today. If you can take my word for it (I forgot to save the results), I got about half the bandwidth with PCI-E 2.0 enabled.

DarkLogix
Texan and Proud
Premium Member
join:2008-10-23
Baytown, TX

DarkLogix

Premium Member

said by Tirael:

However, it requires a registry hack to do so on my CPU (since the i7-39xx series is 3.0 compliant, but does not have the 3.0 certification),

So did you leave 3.0 enabled? if it were me I would.