460 GTX overclocking woes

[A_Dying_Wren]

Hi guys. I've got myself a nice new system as shown in my signature. Basically, I'm having trouble OC'ing my 460 GTX SLI. The fans blow to 100% as recorded by Afterburner (yea I know this isn't accurate) and the temperature for both cards stands at 91C. I'm running at 1.087V 850/1955 and its stable for about an hour of furmark. These speeds and these temperatures are quite frankly rubbish.

The problem is that on the exact same system but with Windows 7 32 bit (running 64 bit now. long story) I ran the system stably at 1.087V 899/2097 with temperatures only reaching 85 for one card and 82 for the other. The fans were not running at 100% (88% and 78%) according to afterburner. I don't hear too much of a difference in fan speed subjectively.

So basically, on a 64 bit OS I get worse temperatures, lower clocks whereas on the 32 bit OS I get better temperatures, higher clocks with almost the exact same system (I didn't have the vertex 2 on the 32 bit OS and the 32 bit OS was W7 ultimate whereas the 64 bit OS was home premium).

Any help would be appreciated.

 

[Jules]

which gtx 460 do you have? I just picked up the Gigabyte GTX 460 1gb and im able to push 825/2000 with a 0.962v

 

[Keysplayr]

Huh? Did you buy factory overclocked cards? Or the standard 675MHz core GPUs?
Because an 850MHz o/c is anything but rubbish IMHO. That's 175MHz over a stock card.
And, I don't see why a 64-bit OS and a 32-bit OS would have anything to do with temps of the cards at similar tasks. It could be just reporting incorrectly be it the 32 or 64 bit OS.

 

[SolMiester]

Didnt Anand used to have a bit of fun clocking CPU's (AMD) on x64 systems?, wonder if its a resources thing?...though cant say I have heard of many with a stable 900 core on Fermi as yet!

 

[A_Dying_Wren]

I've got a Palit 460 GTX, the slightly overclocked one which starts at 700 MHz. I suppose "rubbish" is putting it too far but I am still rather annoyed by the great disparity between the 32 bit and the 64 bit OS performance.

@Jules: Thats a pretty decent overclock you have given the voltage. I heard you get more performance out of the card if you emphasize a bit more on the core clock.

@SolMiester: There are a fair few people in other forums who are running stably well beyond 900 MHz. It's just here where we don't really have a dedicated thread for OC'ing the GTX 460 (one got sidetracked and the next one got locked)

@Keys Its "rubbish" insofar as I know these cards can be stable at a fair bit higher than what I have now for some odd reason.

 

[Ben90]

I have some (probably incorrect) theories to why this is happening.

There is no doubt that this phenomenon occurs with processors however. Unless an application specifically benefits from 64-bit code, you can be sure every record broken from extreme overclocking takes place on a 32-bit operating system.

Is there anything in the driver that could be causing this? AFAIK Nvidia uses two seperate drivers for 32/64-bit.

 

[kami]

Are you running the latest version of afterburner? 1.6.1 is when GTX 460 support was officially added.

Also it's possible the temperatures you are reporting are accurate for an overclocked Palit. When I was shopping for a GTX 460 I read several negative reviews on the Palit cards, specifically in regards to their custom cooling solution.

Also, not every card is guaranteed to hit 900Mhz+

 

[Keysplayr]

I've got a Palit 460 GTX, the slightly overclocked one which starts at 700 MHz. I suppose "rubbish" is putting it too far but I am still rather annoyed by the great disparity between the 32 bit and the 64 bit OS performance.

@Jules: Thats a pretty decent overclock you have given the voltage. I heard you get more performance out of the card if you emphasize a bit more on the core clock.

@SolMiester: There are a fair few people in other forums who are running stably well beyond 900 MHz. It's just here where we don't really have a dedicated thread for OC'ing the GTX 460 (one got sidetracked and the next one got locked)

@Keys Its "rubbish" insofar as I know these cards can be stable at a fair bit higher than what I have now for some odd reason.

IIRC, the palit cards had a model that was missing the VRM heatsinks. Don't know if this was by design or something QA didn't pick up on at Palit.
I can't remember the thread I read this in. I'll try to dig it up unless somebody can do it first.

EDIT: Here it is.

http://forums.anandtech.com/showthread.php?t=2089737&highlight=palit+vrm+missing

 

[A_Dying_Wren]

Ben90 - You're probably right on it having something to do with 64 bit vs 32 bit software. I think I'd be better off forgoing that extra 4+GB of ram for a higher clock. Has any one heard of such instabilities in 64 bit OS's with regards to Afterburner, drivers and or the OS?

kami/keys - the point is my cards ran stably at a higher clock with lower temperatures on a 32 bit OS (vrms notwithstanding) with the same MSI afterburner 1.6.1 software as opposed to the worse in every regard OC of the 64 bit OS. I'm extremely peeved at Palit for not including a VRM heatsink. I was fully aware of it but Palit is the only vendor here at the moment.

 

[Jules]

I've got a Palit 460 GTX, the slightly overclocked one which starts at 700 MHz. I suppose "rubbish" is putting it too far but I am still rather annoyed by the great disparity between the 32 bit and the 64 bit OS performance.

@Jules: Thats a pretty decent overclock you have given the voltage. I heard you get more performance out of the card if you emphasize a bit more on the core clock.

Yeah i have yet to mess around with it more. Im getting around 68c on load with the fan at 48%. Pretty happy with the card

 

[Ben90]

This is just a shot in the dark because it probably wont work, but try downloading the 32-bit driver and see if it reverts anything to how it was. Hopefully it doesn't have one of those stupid checks that won't allow it to install if its not a whitelisted OS.

If that doesn't work I think you might just have to settle with the fact that you aren't getting as great of an overclock on a 64-bit OS. The original Phenom II owners had to live with this and its not the end of the world. Personally I wouldn't go back to 32-bit like you mentioned because eventually your going to want the features 64-bit gives.

 

[A_Dying_Wren]

This is just a shot in the dark because it probably wont work, but try downloading the 32-bit driver and see if it reverts anything to how it was. Hopefully it doesn't have one of those stupid checks that won't allow it to install if its not a whitelisted OS.

If that doesn't work I think you might just have to settle with the fact that you aren't getting as great of an overclock on a 64-bit OS. The original Phenom II owners had to live with this and its not the end of the world. Personally I wouldn't go back to 32-bit like you mentioned because eventually your going to want the features 64-bit gives.

I believe the drivers do check for that. Accidentally tried to install a 64 bit driver on the 32 bit OS and it wasn't allowed but I gather that 32 bit software on 64 bit OS should theoretically be fine. I'll try it out anyhow. Thanks for the advice.

I've backed down my overclock and just testing it bit by bit higher. I can get 861/1955 stable at 1.050V but the temperatures are scaring me. I guess I'll have to settle with something like that.

 

[Jules]

hmm im able to get 850/2000 with a 1.012 vcore. Not sure if its worth it over 825/2000 with a 0.975v