gtx 570 3dmark 11 question

[Riznarf]

Hey all-

So I've been OCing my gtx570 trying to get a stable OC and Ive had some confusing results from 3DMark '11. Check it:

732/1900 0.975v (STOCK) - 5740
850/2000 1.038v - 6428
880/2000 1.038v - 6595
890/2000 1.050v - 6646
900/2000 1.075v - 5738

So, I encountered instability when I attempted a 900/2000 @ 1.050v so I bumped it up to 1.075v and although it passed the stress test I got a score lower than stock...any ideas why???

Thanks.

 

[patonb]

Whats your temperatures?

 

[Riznarf]

Whats your temperatures?

nominal. high 70s to low 80s under 100% stress

 

[GhOsT1321]

Perhaps your 520 watt power supply isn't enough. Your card can consume up to ~300 watts without an overclock.
ASUS GeForce GTX 570 Review - Page 25/31 | techPowerUp

 

[Riznarf]

Perhaps your 520 watt power supply isn't enough. Your card can consume up to ~300 watts without an overclock.
ASUS GeForce GTX 570 Review - Page 25/31 | techPowerUp

sig is out of date, i have a 800 watt PSU now

 

[Slaymate]

and although it passed the stress test I got a score lower than stock...any ideas why???

It sounds like you passed one stress test but you failed the 3DMark 11 stress test. Every GPU, or even CPU, has a maximum limit. This limit can vary depending upon the configuration (cooling, voltages, drivers, etc...). 1.075v might be more than the card can handle reliably at your ambient temperature, even if the card's reported temp is in the safe zone.

It could also be the card's memory that has hit it's limit. At 800/2000 you may be generating 30GB/s (random number) of memory bandwidth, but at 850/2000 you might be generating 40GB/s (random number) of memory bandwidth. As you increase the GPU speed it increases the memory bandwidth but there comes a point when the memory chips become saturated and the extra bandwidth just congests the memory busline. This can result in a lose of performance, just like your experiencing.

 

[Fat.Clown]

it could be the video card is throttling itself to keep temperatures in check.
yeah, newer cards actually cuts back on performance to keep itself from overheating. AMD too, not just Nvidia.

 

[Riznarf]

it could be the video card is throttling itself to keep temperatures in check.
yeah, newer cards actually cuts back on performance to keep itself from overheating. AMD too, not just Nvidia.

my temps are well within optimal rages. stress tests but it low 80s and gaming it only gets to high 70s. Id be surprised if it throttled back performance for those temps...

 

[Riznarf]

theres also a setting in afterburner to "force constant voltage". should that be enabled?