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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
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
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...
 
OP
Lavacon

Lavacon

Member
Joined
Nov 24, 2009
Location
Lost in NH
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.
 
OP
Lavacon

Lavacon

Member
Joined
Nov 24, 2009
Location
Lost in NH
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
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
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.
 
OP
Lavacon

Lavacon

Member
Joined
Nov 24, 2009
Location
Lost in NH
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.
 

Xtreme Barton

Member
Joined
Jan 17, 2004
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 ?
 

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
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?
 
OP
Lavacon

Lavacon

Member
Joined
Nov 24, 2009
Location
Lost in NH
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.
 

Xtreme Barton

Member
Joined
Jan 17, 2004
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 ??