FrankyDeluxe

He Guys,

Yesterday i recieved my second Radeon 4870. As happy i was with the performance of a single 4870, so dissapointed i am after adding the second one. In COD4 im experiencing stuttering and short hickups now and then. In Frontlines i'm experiencing some stuttering too and some tearing as well.

I didn't need the extra card for these games really, because i already reached 60FPS average @ 1680x1050 and everything maxed out with a single 4870. Acutally i hoped to see a little gain in Crysis, but crossfire gets me significant lower framerates then with a single card (~25 instead of ~40).

I have tested with the 8.6 and 8.7 beta drivers and with the hotfix. doesn't really make a difference. I have the CrossfireX option in the CCC checked. Enabling Catalyst A.I. doesn't make a diffrence either.

I know the drivers are not matured yet, and Crysis is not scaling very well with Crossfire, but something is obvious not good here. I saw a couple of benchmarks showing at least a 20% performance gain in Crysis, and read nothing about lagging and stuttering in COD4. Did i miss something, or do i have to wait for Catalyst 8.7 to fix all this?

Thanks in forward!

__________________
"The best way to predict the future is to create it yourself."

Robilar

I have had a tremendous improvement in COD4 from 1 card to 2.

Are you certain your power supply is sufficient to support a pair of HD4870's under load?

From the reviews I have seen, 750W is the recommended minimum.

imortal98

Had a similar problem a while ago.

it really all depends on your setup...everybodies system setup is different.
Making the variablity if you think of it very unlikely to be the same as all the benchmarks and stats that everybody posts according to there systems. you have to put that in mind.

Edit: a 20% increase in somebody elses post is highly unlikely you will get it as well

And it sounds like you went through all the proceedures to make sure it isnt anything else .

Unless i missed something

So you will have to wait for the new driver updates.

__________________
Member of the OCN Diablo III Club
http://www.overclock.net/case-mod-wo...pleted-tp.html

rx7racer

*takes a look at psu*

I'd say you might want to upgrade your power supply.

I wouldn't run anything under 700W for the 4850's especially if you oc let a lone for the 4870's.

FrankyDeluxe

Oke, but like i said, it already did 60fps average with everything maxed out, so there was nothing to gain there, but i think it's strange it was performing worse with crossfire.

Well i have a 600Watt PSU of pretty solid quality, so it should be enough. My power drain was about 300W with a single 4870, so i don't think that is the problem to be honest.

__________________
"The best way to predict the future is to create it yourself."

Robilar

New drivers?

I have had no lagging or stuttering of any kind with crossfire and I have also run the hotfix (currently using 8.7 betas).

There are a number of other members here as well with CF setups. I have not heard of stuttering issues. Also given that I play COD4 extensively, its likely I would have seen something as well.

imortal98

hmmm you might be right...you might be needing more juice

__________________
Member of the OCN Diablo III Club
http://www.overclock.net/case-mod-wo...pleted-tp.html

rx7racer

I know mine run smooth as silk and from what I hear Grunion say his are silky smooth as well, He's running 4870/4850 right now so if it was common I would say he would have felt that issue himself.

I would try, drivers as Robilar suggested and you are running 16x/16x right?

Robilar

Right so given a 300w drain with a single card, add another 170 for two brings you up to 470w drain on a 600w power supply.

do you know how many power supplies can provide continuous power at 78% of their load?

not too many outside of the mainstream makers (for example, PC Power, Enermax, Seasonic, Corsair, Silverstone).

It's one thing for a power supply to be rated for example at 600w but the reality is that most systems do not draw anywhere near full load. If you look at tests done by sites like hardocp or jonny guru, they test power supplies typically at 80% of load for an extended period.

It's surprising how many power supplies don't pass these tests with flying colors.

FrankyDeluxe

ATI itself recommends a 600W power supply for two 4870's in Crossfire mode, so again, i dont think thats the issue.

Yes offcourse. I got an X38 chipset, so that is not the problem.

__________________
"The best way to predict the future is to create it yourself."