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Crossfire speeds different for each GPU

rob77

rob77

rob77

Associate
Joined
3 Mar 2009
Posts
412
Hi guys

Tonight I put in a second asus 270 and everything is working okay apart from an slight quirk. If I leave everything standard with no AMD overdrive enabled the graphics cards run at different speeds although they are exactly the same brand. They should run at 975Mhz/1400Mhz but unless I have overdrive enabled one card runs at the stock speed (975/1400) and the other at 1115Mhz/1500Mhz. Any idea why this would be? I am using afterburner and rivatuner on screen display to see the clocks.

Cheers
 
Hi gripen90

They are exactly the same card so they should be the same. I have checked in gpuid and they are showing as both the same. The card was used when I got it and hope it hasn't been hacked for higher clock speeds
 
Hmmm I will have to check tonight. Hopefully it should just be a case of flashing the original firmware back.
 
A card "hacked" for higher clocks? That's hilarious phrasing.

I wasn't aware that you could BIOS edit a 270? If I'm wrong, it just sounds like they've edited the BIOS and put the overclock in so it's not reliant on software.
 
You could save the bios of both cards with GPU-Z and flash either one with the bios of the other with ATIwinflash, as long as you keep a backup of both you are safe, the worst case scenario is having to boot with the non-flashed (working) card and reflash the other one with it's original bios.

However, I have a 7990 with one of the launch day 7970s in crossfire, the 7990 has a boost clock of 1000, the 7970 has a fixed 925 clock, with 1500 and 1375 on the VRAM respectively.

I notice no difference if I match their clocks or leave them stock...
 
rob77 said:
Hi gripen90

They are exactly the same card so they should be the same. I have checked in gpuid and they are showing as both the same. The card was used when I got it and hope it hasn't been hacked for higher clock speeds
Click to expand...

Factory overclocked models will appear identical in GPU-Z, often have the same cooler and PCB. Check the actual part numbers on the cards.
 
Running at different speeds isn't actually a problem for xfire though is it? If you aren't encountering any issues then might as well just leave it or even better overclock the other card to match :)
 
Don't know about xfire, but my last two sets of nv cards in sli run at different boost clocks. 1124 and 1097 on cores for my 780's. Identical gigabyte wf models as were my 670's.
 
Thanks so much for the info guys. The second card had been modified in the bios. I have now flashed it back to stock from a bios on techpowerup and is running at the correct speeds.

Gotta say I am impressed with crossfire. I ran it for a short while back when I had some older cards (HD6000 series)and it was no where near as smooth as the current drivers are.
 
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Glad it's worked out. But yeah bios editing isn't that hard to do, when I got my second 7950 "identical" card, it was running with a maximum wattage of 80w lower, wouldn't clock at all, and it kept throttling because it was short on power, no idea why, previous owner must have been a safety 'I will not overclock' person and underclocked it. So I just took the settings from my first card, and edited the second cards bios and flashed it to be identical. Now both clock in perfectly identical.
 
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