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new 3870 Crossfire Setup; Not much faster?

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Boosted98gsx

Member
Joined
Apr 20, 2004
Location
Houston Tx
I upgraded from a single 2900 XT to a dual "3870 Overclocked" from Visiontek crossfire setup. However, my 3dmark06 scores did not improve very much.

Any ideas as to why?
 
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Boosted98gsx

Boosted98gsx

Member
Joined
Apr 20, 2004
Location
Houston Tx
Yup, have crossfireX enabled in the ATI control panel. Both ribbons on the cards, both power connectors on, and an 850w power supply.
 
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Boosted98gsx

Boosted98gsx

Member
Joined
Apr 20, 2004
Location
Houston Tx
crossfirex.jpg
 
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Boosted98gsx

Boosted98gsx

Member
Joined
Apr 20, 2004
Location
Houston Tx
Here is another thing that's bugging me. I have 2 of these cards:

http://www.bestbuy.com/site/olspage...=3870&lp=1&type=product&cp=1&id=1203815034383

and I can find no mention of any special "Over-clocked" edition of the 3870's (non x2) online

Core speeds of "2340MHz overclocked core speed" and yet ATI catalyst doesn't show above 1170 mem speed even with a 3d app running.

ATI tool will not run either for some reason.
 

Reefa_Madness

DRAM Guru Senior
Joined
Feb 26, 2004
Here is another thing that's bugging me. I have 2 of these cards:

http://www.bestbuy.com/site/olspage...=3870&lp=1&type=product&cp=1&id=1203815034383

and I can find no mention of any special "Over-clocked" edition of the 3870's (non x2) online

Core speeds of "2340MHz overclocked core speed" and yet ATI catalyst doesn't show above 1170 mem speed even with a 3d app running.

Is this your card being reviewed?

http://www.neoseeker.com/Articles/Hardware/Reviews/visiontekhd3870/
 
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Boosted98gsx

Boosted98gsx

Member
Joined
Apr 20, 2004
Location
Houston Tx
So then my "over-clocked" mem clock is accurate?

Why then am I barely getting any gains over my old 2900xt with 2 of these in crossfire?
 

Reefa_Madness

DRAM Guru Senior
Joined
Feb 26, 2004
The card looks the same, but my box has "Over-clocked Edition" on the bottom of it, when the card is CLEARLY not over-clocked.

*edit*

Wait, on this page:
http://www.neoseeker.com/Articles/Hardware/Reviews/visiontekhd3870/4.html

when they over-clocked the card, "core clock of 884 and a memory clock of 1292 (2596 MHz)" why do they state the mem clock doubling like that?

(Edit: sorry, I kept changing what I was typing below and in the mean time you guys anwered the question about ddr)

Isn't it because the memory is DDR, or Double Date Rate?

Your memory of 1170 x 2 = 2340. The Spec tab of the linked Visiontek product page at Best Buy shows it to be the memory speed, but the Overview states that it is the core speed...I believe that the Overview is just wrong, the 2340 refers to memory and not core speed.

The review appears to have a math error because 1292 x 2 = 2584, not 2596. Either the "1292" should have been a "1298", or the effective rate should be 2584 and not 2596.
 

Reefa_Madness

DRAM Guru Senior
Joined
Feb 26, 2004
So then my "over-clocked" mem clock is accurate?

Why then am I barely getting any gains over my old 2900xt with 2 of these in crossfire?


My guess is that you've got a CPU bottleneck. Were you using the same mobo/cpu with your 2900?

Might be time to go Intel, in order to get the most out of those twin cards. :D
 
Last edited:

xbiker321

Member
Joined
Jul 14, 2002
Location
Kingman, KS
My guess is that you've got a CPU bottleneck. Were you using the same mobo/cpu with your 2900?

Might be time to go Intel, in order to get the most out of those twin cards. :D

I doubt it, his system is about the same is mine and I score 16,500 in 3Dmark06 easily. I did have a problem though I posted a week ago here and no one replied but it was my crossfire was not being enabled, even though CCC said it was and so did GPU-Z. It would be "enabled" and I would score something like 10,000-11,000. Some strange reason it would work sometimes and I'd score my 16,500. Anywho I got fed up with it because it clearly was a software/driver issue and I formatted my hard drive(s) and installed Vista (I had XP Pro w/ SP3). Now crossfire works all the time for me and I always get my 16,500 3Dmark06 scores.

:screwy: I know.
 

oakstave

Member
Joined
Mar 20, 2007
Location
Oregon
Actually, it's almost certainly a cpu bottleneck.

Alberquerque and I had a little contest with our 3870 crossfire set-ups. With my E6700 screaming hot at 3.5Ghz, I was able to hit 16500. Alburquerque had a superior E8400 and was hitting 19k without breaking a sweat.

There was also some difference in lane speeds, 16x/4x vs. 16x/16x- But it was the cpu scores that really made the difference.

With a Quad, you'd be hitting 20k, but the Phenom can't feed those hungry cores fast enough.

This is also a statement on 3dM06 scoring. They weigh heavily, and I would say unduly, on CPU power.

If you have the full version of 3dm06, post your cpu score, and I think it will be clear what's slowing you down.