HD5850 Overclocking

[WildW]

Hi folks. I've been playing with my new 5850 to see what she can do, and I'm wondering what folks use to stress-test their GPU overclocks, and what my 5850 ought to be capable of. I've seen in online reviews that these ought to overclock pretty high, but I've run into some issues.

My system:
Gigabyte G31M-ES2L with E5400 @ 3.6GHz
XFX HD5850 XXX (stock clock is 755MHz, memory 1120Mhz, I think)
PSU is a Hiper Type M 630W

PSU seems to be stable, 12V rails stay above 12V at full Prime95+FurMark Extreme Burn, so I'm happy enough that my power ought to be okay.

Basically I've tried overclocking with FurMark as a stress-test. Catalyst Control Centre's overclocking options quickly run out of GPU headroom at 775MHz (which seems perfectly stable), and memory can't be overclocked at all. So I then switched to AMD's GPU Overclock utility.

Clocked up to 5870 speed (850MHz core, 1200MHz memory) - I figure the memory are supposedly the same chips as on the 5870 anyway so should be rated for 1200, and the GPU is designed to run at that speed, in theory. Guess there is a reason why my GPU became a 5850 and not a 5870.

Anyway, at 850/1200 FurMark runs just fine, temps max out at 81C under extreme burn, no artifacts visible, and I'm happy. Then I try out the benchmark/demo thing of Stalker Pripyat. . . and I get a video freeze (Graphics stop responding but there's continued hard disk activity, etc) So I figure that overclock isn't stable. AMD GPU Overclock utility has some GPU Voltage options, but the highest value in the list is already selected, so I figure I can't overvolt any more?

So, questions, questions. . .

1) What programs do folks use to test GPU overclocks? Furmark doesn't show artifacts but the thing still crashes. The new Stalker is meant to be DX11 apparently, maybe it tests the parts that FurMark cannot reach?

2) Do I have a lousy 5850 that won't overclock, or did the reviews maybe do like I did and assume their 900+ MHz overclocks were stable when their stress-test of choice looked okay?

edit: Seems I got things mixed up and must've been thinking of 5870 reviews. 5850 results seem to max out below 850MHz. http://www.gpureview.com/gpureviews-hd-5850-overclocking-roundup-article-816.html

 

[NumericalMethods]

I'm not a massive gpu overclocker so the only programs I can really recommend for stress testing are Furmark and OCCT gpu test. The one comment I would make about both these programs is - they are exceptional at stressing the gpu core but don't stress the memory nearly as much.

Because different graphics engines stress the various components by different amounts, the only comprehensive way to test your card for stability is to run overclocked settings for a range of games. Crysis, Farcry2, maybe Grid or Dawn of War2 are good places to start. If you can get stable settings for your card over a range of games you will be halfway to a stable overclock.

Finally, I had a factory overclocked 8800gt that was stable for 18 months. Great card. Then I played Mass Effect and it crashed its ass off. I had to relax the overclock on the card, despite being the factory setting to play that one game. Its just part and parcel of running overclocked components in my opinion. Sometimes there will be problems, but there is no such thing as a free lunch right?

 

[Ares202]

Did you try upping the voltage? Try MSI Afterburn for that and you should get 900mhz

My 5850 is BIOS locked at 775/1125, did you flash yours?

 

[WildW]

I haven't flashed anything. 775/1125 sounds right for the max on mine in CCC. For now I've just left that maxed out in CCC. To be fair that's plenty for any game I have at the moment.

Was not aware of Afterburn until I did some Googling this morning, so I guess I'll play with that. Once you've found some lovely 800+ MHz overclock, is there a simple way to automatically set that up at bootup, rather than open up various programs? Or is the only option to flash the bios?

 

[bunnyfubbles]

flashing the BIOS really isn't that hard, especially since the 5850s are all stock reference for now (that I know of) and thus you should be able to flash any of the already available BIOSes that have higher limites (the ASUS one for example)

 

[AzN]

5850 have lower voltage than 5870. At least that's what I think without looking it up. Upping the voltage produce more heat so that stock cooler might not be up to task unless you have very good air flow in your case.

 

[Paktu]

Did you try upping the voltage? Try MSI Afterburn for that and you should get 900mhz

My 5850 is BIOS locked at 775/1125, did you flash yours?

I have a Sapphire 5850. Never flashed the BIOS, just used the AMD GPU Clock Tool. I'm running Furmark now and MSI Afterburner is showing my clock speeds at 825/1175. Maybe some cards are locked and others are not?

EDIT: Check this out: http://tech.icrontic.com/article/overclocking-the-radeon-hd-5850/ It says the AMD tool bypasses BIOS limitations.

 

[bunnyfubbles]

EDIT: Check this out: http://tech.icrontic.com/article/overclocking-the-radeon-hd-5850/ It says the AMD tool bypasses BIOS limitations.

yup that tool works great, but on another note, that's a very sloppy guide/review

he doesn't suggest using GPU-Z, which is easily one of the most important and easy tools for monitoring temps including your VRM temps

the review also makes ridiculous claims such as because the 285 performs better in the Furmark bench, that the 5850 somehow won't be as good for Doom 3, when BFG10K actually found the 5770 to be faster than his GTX285, I don't think the 5850 is going to be worse off...

The review was also a bit misleading about memory overclocking - from what I understand you won't get errors from your memory due to the new memory controller. The way to detect unstable memory overclocks is to watch for performance drops. If he was getting instability from his stress tests, I would guess he's actually getting it from VRM overheating, which he wouldn't know about because he wasn't using GPU-Z.

 

[Painman]

I flashed my 5850 in order to unlock the clocks and I use MSI Afterburner for all the tweaking. AMD GPU Clock tool will work for those who prefer not to flash, of course.

Stock load voltage for a 5850 is 1.087 volts. 5870 gets 1.162.

I'm not a fan of FurMark/OCCT for stability testing. I prefer to load up a stressful, shader heavy game, play for extended periods and see whether I get crashes/artifacts or not. This time around it was Fallout 3 with all details maxed and heavy amounts of AA. This game loads up the GPU nicely, and yeah, I made it barf several times throughout testing. I just cranked things up little by little over the course of about a week. First the core, then RAM.

My final OC is 1000/1250 with 1.287 volts. That's a bit high on the volts, but the core is watercooled and PowerPlay is still active for idle mode. I've got some extra heatsinks and a fan on the VRMs and they're staying comfortably cool.

 

[WildW]

I'm not a fan of FurMark/OCCT for stability testing. I prefer to load up a stressful, shader heavy game, play for extended periods and see whether I get crashes/artifacts or not. This time around it was Fallout 3 with all details maxed and heavy amounts of AA. This game loads up the GPU nicely, and yeah, I made it barf several times throughout testing. I just cranked things up little by little over the course of about a week. First the core, then RAM.

The way Fallout 3 crashes, how would you ever know when it was due to overclocks?

 

[Painman]

Fallout 3 is very stable on my rig, otherwise I wouldn't stress test with it. Pretty easy for me to tell if a GPU OC is unstable with the game, as it'll usually start artifacting and/or go into recovery within half an hour.

 

[WildW]

I recall when I first got Fallout 3, it would crash very frequently, and the consensus on here was that it was a Fallout 3 thing. Then again, I'm pretty sure it just didn't like my 9800GTX+, as it ran far more stable on my 4670. Not that my 4670 ran it well enough, it just didn't crash.

It's nice to be in the Red camp again.