HD3870 X2 / GPU-Z Question

[gsipruitt]

Hey guys,

Quick question...I have crossfired HD3870 video cards. Upon using GPU-Z, it shows that no crossfire is detected (while CCC shows that it is).

Another question I have...when using GPU-Z, the first video card shows a bus interface of "PCI-E x16@x16" while the second card shows a bus interface of "PCI-E x16@x4". Why the discrepancy? Is this normal?



Card 1 is on the left, card 2 on the right.

Thanks in advance for any knowledge put forth.

 

[dark2099]

CCC will show a tab for CrossfireX if it is available, it does not mean it is running, click on the CrossfireX tab and enable it by clicking the box. As for the bus interface being different my guess is you are using a motherboard that has 1 PCI-E 16x slot that is blue and 1 PCI-E 4x slot that is black. What motherboard are you using?

 

[gsipruitt]

Thanks for the quick reply! I didn't mention it...but the crossfire box is checked within CCC.

Here's an image of my motherboard stats:

 

[dark2099]

The chipset of your motherboard will only support 16x/4x setup for crossfire, and if you are having trouble getting it working properly you can check out the crossfire thread here.

http://forums.techpowerup.com/showthread.php?t=51219

 

[gsipruitt]

Is the 16x/4x combination common? Or is it a terrible disadvantage to crossfire?

Also, my crossfire seems to be working fine...as far as I can tell, it just doesn't show up in GPU-Z. If crossfire wasn't working what-so-ever, would I be able to check the box in CCC?

 

[gsipruitt]

Little update on this...

I followed the steps in that link and crossfire still does not show in GPU-Z. However, CCC shows that is enabled and I have no reason to believe it's not.

 

[dark2099]

The next idea I have is uninstall your drivers using the following guide and then use the crossfire guide to set them up again and see if that works.

http://forums.techpowerup.com/showthread.php?t=52502

 

[gsipruitt]

Is it possible that GPU-Z is not picking up the motherboard/video card combination?

 

[boogah]

One way to test if it's working is some quick benchmarks

with it enabled in CCC run the benchmark then disable it then run the benchmark then compare the score if it's higher when it is enabled it's working for you.

 

[gsipruitt]

I ran a 3DMark06 (which also doesn't recognize crossfire) pixel shader test without it enabled and received 330FPS and with it enabled, 680FPS. Therefore, I imagine that crossfire is indeed working.

Therefore, I'm guessing that the programs aren't recognizing the motherboard/card combination.

 

[tamazoid]

I seem to have the same problem as well. I'm using a Asus P5K-E/WiFi-AP motherboard(which also only support 1 PCI-E 16x and 1 PCI-E 4), and I can see that Crossfire is enabled in CCC, but not in GPU-Z. I did both the steps in removing and installing the drivers, but it's still the same.

I did some benchmarks in 3dMark06, and it seems to work. So I'm guessing that GPU-Z just doesn't recognize it. But I do find that some games don't seem to run in Crossfire. Does that mean that only some games support it? Thanks

 

[W1zzard]

it is possible that gpu-z is wrong about the crossfire support.

however, i havent seen a single issue where gpuz was wrong about pcie lanes. some mobo and gfx vendors actually found issues with their bios/software using gpuz

 

[gsipruitt]

I don't think either of us are saying the PCI-e lanes are wrong in GPU-Z, they're acurately represented (at least in my case).