Overclocking lowers PCI-E speed on 7970s?

[OVerLoRDI]

So I loaded up GPU-Z to keep an eye on temps and such.

Stock:

Exactly what you would expect for SB with two cards

Oc'd:

drops to PCI-E 1.1

At least that is what GPU-Z says. Is there another way to check bus speeds. I want to rule out if GPU-Z is reading this incorrectly.

 

[Shmee]

hmm that is odd. Do you notice a drop in performance, or rather an increase due to clock speeds? thats what should matter.

 

[Ferzerp]

Put it under load and see what happens. If I recall correctly, that's a power saving feature.

 

[ShintaiDK]

Cards idle in PCie 1.1 and such. Very normal.

 

[Termie]

Put it under load and see what happens. If I recall correctly, that's a power saving feature.

To learn more, click on the little question mark right next to the "bus interface" box in GPU-z.

 

[Magic Carpet]

Cards idle in PCie 1.1 and such. Very normal.

Now, why do they do that? Is it.. just to conserve power? Never paid attention to that.

 

[ShintaiDK]

Now, why do they do that? Is it.. just to conserve power? Never paid attention to that.

Yes.

 

[Don Karnage]

So I loaded up GPU-Z to keep an eye on temps and such.

Stock:

Exactly what you would expect for SB with two cards

Oc'd:

drops to PCI-E 1.1

At least that is what GPU-Z says. Is there another way to check bus speeds. I want to rule out if GPU-Z is reading this incorrectly.

Could you run 3dmark11 and heaven on max overclocks and post a screenshot? I want to compare

 

[(sic)Klown12]

While having GPU-Z open, run a windowed 3D program and make sure it's going back up to full speed with load. While it's normal for the bus to drop when in idle, it's weird that it'd drop to different modes depending on whether or not you're overclocking. I know my 7970 doesn't do that.

 

[blackened23]

Never happened here

 

[OVerLoRDI]

Cards idle in PCie 1.1 and such. Very normal.

derp derp. I feel dumb.

Ran heaven in a window and saw the bus speed jump back up to 2.0.

Seems like I got unlucky since the bus speed seemed to be swapping back and forth occasionally during desktop usage and I kept catching it at the wrong time.

 

[Kenmitch]

derp derp. I feel dumb.

Ran heaven in a window and saw the bus speed jump back up to 2.0.

Seems like I got unlucky since the bus speed seemed to be swapping back and forth occasionally during desktop usage and I kept catching it at the wrong time.

Why feel dumb? You learned something new and others that read your thread did also

 

[OVerLoRDI]

Why feel dumb? You learned something new and others that read your thread did also

:thumbsup:

Could you run 3dmark11 and heaven on max overclocks and post a screenshot? I want to compare

I don't have the full version of 3dmark11. See this thread for mine and many other's heavens results:

http://forums.anandtech.com/showthread.php?t=2237529

My max overclock so far is 1225mhz @ 1.23v on these cards and those results aren't in there. Soon I'll get my CPU oc'd and see if I can push my 7970s farther. Then I'll get your results