Does this sound like a power supply or cooling problem?

[chewychewbacca]

AMD Phenom II x 720 - Overclocked to 3.6GHz (from 2.4Ghz) running at 1.4v instead of 1.3v
2x Radeon HD4870 512mb in Crossfire (Asus EAH4870 Dark Knight)
500gb and 2TB Hdd
OCZ Reaper HPC 4GB (2 x 2GB) DDR2
Dark Knight-S1283V CPU Cooler
CORSAIR CMPSU-750TX 750W Power Supply

All these are in a raidmax smilodon case. The side window of the case got cracked, and I took it off and it seems like it runs better that way. Still, I'm not sure if it's sufficient to cool my setup. It seems like I've never had my graphics card run stable on graphics intense games.

When I play BF3, I was able to play smoothly for a bit, but then it always gets stuttery, even when I turn it down to Low.

I'm wondering how I can improve this, because I'd like to be able to play BF3. Is my power supply able to handle my components? I figured when I bought the PSU, if I bought a good quality PSU, 750W would be ample.

Currently using Catalyst 11.10 Preview.

Tried to play a bit and monitored using Afterburner.


Results:
GPU1 Min Temp: 61C Max Temp 74C
GPU2 Min Temp: 53C Max Temp 75C
GPU1 Max Usage 75%
GPU2 Max Usage 78%
GPU1 Fan Speed Max 80
GPU2 Fan Speed Max 89

Still Stuttering / feeling like dropped frames.

 

[WR2]

CORSAIR -750TX is plenty of power.
Your GPU temps look fine too.

What about your CPU temps under load?
Have you thought about testing stability and performance with a single GPU?
Compare that to your CFX results.

 

[g-unit1111]

What thermal paste did you use? I know Xigmatek includes really cheap white paste with their fans, try using something like Arctic Silver 5 instead and maybe that will help.

 

[g-unit1111]

MX-4 and Noctua NH-1T are great compounds as well. Probably a degree or two higher than AS5

I use Thermalright CFII at work and it is quite excellent - it keeps my i3-2120 cool to 19'C on idle, maybe 25' - 26'C on full load.

At home I use EVGA's Frostbite - it's decent but not that great.

 

[g-unit1111]

what cooler are you using/what is your ambient temps?

I just use a regular Hyper 212+ and I installed a spare Antec fan from an old case as the second fan.

 

[chewychewbacca]

I use arctic silver 5 but haven't replaced it or anything in two years. Maybe a better case like the HAF-X might help, especially with airflow? My case is crap anyways. What is a worthwhile GPU to upgrade to anyway? I might just want to get out of this crossfire mess altogether.

 

[g-unit1111]

I use arctic silver 5 but haven't replaced it or anything in two years. Maybe a better case like the HAF-X might help, especially with airflow? My case is crap anyways. What is a worthwhile GPU to upgrade to anyway? I might just want to get out of this crossfire mess altogether.

A new case certainly wouldn't hurt - you might want to read the article that was just posted on air cooling.

If it's Crossfire that's giving you so much trouble it's probably a driver issue. I know it's a pain but you might want to clean out your system and do a fresh install of Windows.

 

[WR2]

I'm thinking that a Radeon HD 6950 would be the minimum upgrade that would get you better performance than HD 4870 CFX.
You could be having driver issues with some of the new games, with drivers optimized for newer hardware.

Your GPU temps are telling me you don't have a real case issue, although a new case could help drop temps some. HAF-X is probably more case than you need to do that.

What are you getting for CPU temps?

 

[WR2]

What case and what monitor resolution are you working with now?