CrossFireX Performance Questionable

unixman32

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I've been reading around the internet and I've noticed a lot of people mentioning that Cross-Firex setups can really improve performance yet most games don't use the full potential of 2GPU's and most of the time an insane amount of video ram is useless because no games are built to utilize that.

I personally have X2 HD 5770's CrossfireX and I've noticed almost doubled performance in certain games. And terrible performance in others including micro-stutter and shadow flickering issues. Dirt2 ran at 28-30 FPS on a single card everything on Ultra High with 16XAF and 8XAA. And with the 2nd card It runs solid 60FPS and never changes. For some odd reason if I disable v-sync it drops to like 5FPS weird bugg.

I've noticed with games like Assassins Creed II, Splinter Cell Conviction, Prototype, GTA IV, Just Cause 2 and others that the games run at 60FPS or higher if v-sync is disabled but randomly drop to the 20's and 30's even when the scenery doesn't change. I've heard with some games that companies port over from X-BOX 360 the performance sucks on PC's even with the best performance parts.

My question comes down to thinking games don't use all the potential of Cross-Fire/SLI setups.
Using EVEREST with my G15 keyboard I can monitor GPU utilization and even the games that run the slowest like GTA IV my graphics cards never even hit 50% they jump between 15%-30% on both cards. And the game runs terrible slow.

Now, I can run Crysis on Ultra High with no AA at high 50's to 70's FPS.
What is the deal with this?

Im thinking it's very similar to when Multi-Core Processors first came out. They had tons of power, but they had no applications using more then 1 thread and nobody saw a large performance increase.

Some feedback would be nice on this subject.
It's actually very aggravating considering I payed so much for both cards.

 

unixman32

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I have the AMD Phenom II X3 720
But I have the 4th core unlocked and I have it overclocked to 3.2Ghz

the 4th core is perfectly stable and I LOVE IT!
Quad-Core for the price of a Tri-Core.
 

unixman32

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Motherboard: ASUS M4A79XTD EVO

CPU: AMD Phenom II X3 Unlocked 4th core overclocked to 3.2Ghz

RAM: 4GB OCZ GOLD DDR3 overclocked to 1333Mhz

Graphics: X2 HD 5770 (Juniper XT) Overclocked Core=950Mhz Memory=1350Mhz CFX

PSU: COOMAX GreenPower 950W Modular PSU

HDD: Two WD 1TB 7200RPM and one WD 160GB 7200RPM

OS: Win7 Home Premium 64bit / Ubuntu 10.04 AM-64 build On separate HDD's I don't like partitions.

PCI-e lanes are 2.0 I think one is 16X and the 2nd is 8X and I have the reference over-clocked from 100 to 105
 

sabot00

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Don't overclock PCI-e lanes, that's pretty much the worst form of overclocking.
The entire PCI-e specification was built around 100MHz, all of the card calls, latencies, and cycles are designed to fall in-line with the 100MHz refresh rate, at the very least overclock to 200MHz.

Some games just don't scale well.
 

sabot00

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I don't think it's that general, it depends on the game and level of detail, if you had a level with 1 light and a cube then you can probably turn AA up to 32xSSAA.

However turning AA down from 8xAA to 4xAAA would be better performance and probably better quality.