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Poor 4870 Cross Fire Performance

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Lavacon

Member
Joined
Nov 24, 2009
Location
Lost in NH
I know this is a beaten topic, but, I figured it doesn't hurt to ask for some opinions :)

The system I am running is in my Sig.

I am comparing my results to the $700 pc shown recently on THG
http://www.tomshardware.com/reviews/system-Builder-Gaming-PC,2509-9.html

Using the same benchmark settings on Far Cry 2 for Instance, I am hitting 42fps avg with my cards OC'd to 800/1100. Single Card performance is around 36 FPS on the same benchmark.(Ultra High Quality, 4x AA 1680*1050)
This puts me 9fps under the lesser system used in their guide.

Really? A gain of 6 fps using 2 cards?

All drivers are up to date and installed clean.
PCI-E is locked at 100 in bios.
My overclock is solid and my components are for the most part better.

What gives?????

PS: Running W7 Ultimate
 
Welcome to the wonderful world of SLI/Crossfire... 1 great GPU over 2 lesser GPUs anyday.

On a more serious note. Im not sure why you would be seeing those results. I figured it would scale better than that...
 
Yup, 36fps single card vs 41-42 Xfire.

I would have bought a 5XXX series had I not already had a 4870. It made more sense at the time to pick up another 4870 for $125 and go for Xfire until Ati & Nvidia goto war in the spring.
 
1 is a Sapphire 512 and the other is a Diamond 512. All bios listed on techpowerup are from 2008. I suppose having 2 different cards could be a problem, but, being reference models, I don't see where the problem could be. Both are 750/900 @ stock
 
2 models should NOT be the cause of this issue. Even if they were clocked differently, I believe in Crossfire it just takes the lower cards' clocks for both.
 
From what I understand, the lower clock is taken.

Mr Dog... what do you think about adjusting the PCE-E frequency in the bios? I am locked in at 100 as that is the rule of thumb. I have heard mixed things about adjusting this.
 
i agree that two different brand cards shouldn't be the issue i was just curious to see i could find a match for a new flash ..

another curiosity is what are you temps at under load ? no stutters ?
 
It does take the lower clock...

You can try raisining it. 105-110 that may help a bit. But I dont believe this is the issue either as I dont believe they raised their PCIe frequency in the benches you listed.

WEre you running the same drivers as the bench?
Have you tried different drivers?
 
I ran the same drivers as the benches and even ran a newer version to see if it made a difference. Clean install and uninstalls of said drivers.

I keep my fans running at 50% while gaming @ stock, 70% when OC'd I like my temps under 60 degrees. The 4870 runs HOT. if I leave it up to ATI to control the fans, the cards idle around 67 degrees.
 
there is one up for i think it said august of 2009 for the saphire which can be used on you diamond as well .. what version do you have on the two ??
 
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