Crossfre setup, one card clocked faster than the other, normal?

[Socio]

Just curious;

I have two identical HIS 6950 Radeons, same bios, same everything in a crossfire configuration.

I noticed today the card that is the primary adapter has a GPU ( core) clock speed of 840 MHz and Mem clock of 1280 MHz the linked adapter card has a GPU (core)clock of 880 MHz and Mem clock speed at 1300 MHz.

It is normal for two identical cards in a crossfire configuration to have different GPU & Mem speeds?

 

[Termie]

No, that's not normal. Neither of those cards are at reference clocks actually. Are you sure they aren't different overclock models?

Either way, you can simply set both cards at the same clocks. I believe Catalyst Control Center allows that, but you're better off running MSI Afterburner, which will give you more control.

 

[tweakboy]

Who's ? oh HIS Yes you can use different clocks. Like with evga or msi app , you can sync them or not sync them. gl

 

[Socio]

No, that's not normal. Neither of those cards are at reference clocks actually. Are you sure they aren't different overclock models?

Either way, you can simply set both cards at the same clocks. I believe Catalyst Control Center allows that, but you're better off running MSI Afterburner, which will give you more control.

They are both HIS 6950 IceQ X Turbo 2GB cards.

I will test out that MSI Afterburner, thanks for the tip.

 

[Termie]

OK, your cards are 840/1240 models, so for some reason, one of them has been flipped to a 6970-like state, running at 880/1300. That sounds like a second BIOS even, but you said they're running the same one.

Yeah, just go ahead and equal them out in Afterburner.

 

[Socio]

I purchased the 2d card used and both have a bios version of 013.010.000.007 under the info tab in catalyst, the only difference is the bios portion is the bios part number. However that second card does show a 880MHz core 1300MHz Mem and slightly higher memory bandwidth under that tab.

So it appears you are right the previous owner must have "flipped the card to a 6970-like state".

Looks like my best bet is to switch cards so that the faster one is the primary and can take advantage of the extra shaders or perhaps figure out how to flip my primary card to match.

Going to research the latter.

Edit; I checked both cards with GPUz both have the same shader count 1408 so what ever was done to that second card did not turn on the extra shaders so no advantage there.

The other downside is according to the GPUz sensors is that the 2nd card is idling 10 degrees hotter than the other one.

 

[Termie]

No need to worry. Afterburner can override the bios settings, other than shader count, but luckily that's not an issue.

Are you sure the second card (in the bottom slot) is idling higher? It should be the top card that's hotter. I might just run the used card on its own in the top slot to make sure it's actually running correctly in its own, including idling correctly.

As for switching slots, it doesn't matter if the faster card is in the top slot. The system will run each card at its own speed, but will result in overall performance equaling what the slower card would do, as the faster card will simply not work at full capacity.

 

[Socio]

I switched slots just to see if it made any difference and the faster card still remained 10+ degrees hotter at idle. I then tried to under clock the faster one with afterburner to match the stock speed of my original card, but still remained hotter.

I did some research found a couple programs called ATi WinFlash and RBE and a video on youtube that showed I could unlock the shaders using them.

So I saved the bios from my original stock card used them in RBE to change the shader count and then flashed the faster card with the altered shader count bios.

It changed the core and mem clock back to reference clock settings and it now runs a lot cooler, the same as my other card, however it did not increase the shaders.

I am guessing these HIS Radeons can't be shader unlocked.

 

[Termie]

Sounds like you found a solution. Unlocking cores doesn't add much performance, so no big loss. Keep in mind that for clock speed variations, you can just use afterburner. No need to flash.

 

[Socio]

Sounds like you found a solution. Unlocking cores doesn't add much performance, so no big loss. Keep in mind that for clock speed variations, you can just use afterburner. No need to flash.

Might play with that today, thanks for the tips!

 

[Durvelle27]

I use Afterburner to synchronize clocks when using CrossFire.