Q about GPU OC'ing

For as long as I can remember I've had my GPU at 800/1100 clocks. I never really bothered to go past that until recently. OC'ing to clocks of 830/1130 causes GTA4 to crash after 20 mins or so of playing, though any other game works fine w/o crashes or issues.

Well, Ive been reading alot of posts lately concerning GPU OC's and some people have clocks like 810/1090, 790/1100, 750/1080. Basically, different increased values for the core and memory. I always thought that if I raised core by 50, i would have to raise memory by 50 as well...but I guess not. Can someone explain this?

Also, (in my case GTA4 crashing at clocks of 830/1130), how would one determine the culprit whether its too high memory clocks or too high core clocks causing game crashes/graphical issues?

edit: I figure I might as well ask here; What do you use to monitor GPU temps? GPU-Z and Everest both read about the same values but everest usually being lower by 2cs. On the other hand, MSI Afterburners temp reading in-game never passes 78C even after hours of gaming. Weird.

 

what you're remembering is shader clock, usually shader and core clocks used to be linked...
you can increase core and memory clocks disproportionately.. As for determining which one is the culprit, I'd say trial and error...Although i'd guess memory clock in this case coz IIRC, GTA4 used to eat a lot of video memory..

 

I was always told by other overclockers to stabilise the core first and then raise the memory clocks to reach your max overclock. The core actually does most of the work creating video output. The memory is used by the core for storing textures.

Remember that unless the bandwidth is being used up raising the memory clocks may not show much of an increase in your FPS on the other hand raising your core will. Raising both clocks will overall increase the performance output of your card. As the 5870M already has quite a good bandwidth if like me who is running 1600x900 its more important I get my core higher for better performance, I just find 800/1100 is a sweet spot for me personally.

You will also notice that if you raise the core too high it will freeze/lockup/crash but if you raise the memory too high it will artifact.

Every game or program is different and handles overclocking differently so some programs will crash at lower clocks some at higher. You may also notice different results by changing the settings in GTA 4 because I seem to remember it has a VRAM usage monitor in the options menu.

Is the driver crashing/stop responding? or the laptop itself?

I always use HWINFO sensors they are most informative for me personally.

 

@Dallers
I get the error 'GTA4 suddenly stopped working'. Just a crash to desktop really.
Thanks for the info. Completely answered my question. Very informative.

Does HWINFO show temps in-game as well as FPS ala MSI Afterburner?

 

You mentioned that your overclocking your CPU as well remember that GTA 4 is very CPU intensive. Could be causing the crash.

Yes HWINFO logs min/current/max temps so its very helpful to run in the background while you are gaming so that you can check your temps once your finished.

 

HWiNFO32 doesn't show temps while in game (if you meant in a corner of the screen with the game maximized) and definitely doesn't show fps, it' still a great tool for monitoring.

 

Just use FRAPS for FPS.

 

Oh ok thats what I thought. MSI Afterburner wouldve been perfect only if the temp readings in-game weren't way off compared to GPU-Z and Everest....

 

That's odd. In my experience, too much GPU oveclock leads to artifacts and memory overclocks are more likely to cause lockups.

 

Normally overclocking the Core will cause a lockup and memory will artifact and then lockup if pushed too far from my experience. However I have only ever overclocked ATI cards I dont know if there is a difference because of the separate shader on an Nvidia.

It might just be that your memory was too high for the core clocks you raised it too and then it artifacts. Its all about how much power is getting to the card and trial and error because I can handle a higher core with a lower memory and vice versa.

 

Friends, does anyone use Auto-tune in AMD OVerdrive for the 5870M? I just tried it and I got what looked like a multi colored Curtin after about 10 seconds that replaced my wallpaper, but I was able to recover with Win7 Task manager.

 

That "curtain" means it is running the tests, the screen will remain like that until it's finished and it will take some time. The max OC auto-tune gives you might not be entirely stable. in some games though.

 

Auto tune takes a loooooooooooooooo.......ng time to complete, it says I can reach stable clocks of 870/1155.

The lockup and artifacts from hell says it cannot. Self testing is best to find your ideal clock settings.

 

870/1155 you say? I need to run it and see what it gives me