HD7870XT (Powercolor MYST) temps keep rising in Kombustor

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Shodin10k

Gawd
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So i'm having an issue, and am trying to figure out if this is normal or not. I have overclocked my 7870xt to 1150/1500 (+10% power) and trying to use Kombustor burn-in to test to see if its stable. All is going well until ~30 seconds in its starting to pass 80c, and keeps rising to go past 90c. I quickly turn the test off (before I damage the card), and let the temps drop before I try it again , and lo and behold it happens again. Now the card doesn't artifact when going up to 90c, my only issue is with the test, the temps just keep going up.

I put a custom cooler that I had laying around (because the stock one sucks and is loud) http://www.arctic.ac/en/p/detail?sArticle=22.?
Arctic Silver 5 paste was the TIM used. During testing using Kombustor, the heatpipes get very very hot as well as the fins.

While testing on Kombustor the fan is set at idle 50% and keeps rising to match tempatures (i.e. 100c/100% fan speed)

Now the strange thing is that I can game on this fine. Playing BF3 for ~4-5 hours straight, the card never broke 74-75c. 3Dmark11 was the same (never breaking past 74-75c). Other less demanding games never broke past 70c. Idle temps is around ~31c

So my question is that is this normal for Kombustor burn in to keep raising temps like that?

Thanks for any suggestions or help.
 
Kombustor and other GPU burn in utilities put an artificially high load on the GPU and use them in ways they're not intended to be used in gaming (some of the whitepapers we get from the GPU makers warn about damaging OC'ed cards with tools like that). Since they don't represent how a GPU is used during gaming, they really aren't a good indicator of the stability of an OC anyway - you can be perfectly stable in Kombustor or Heavan or whatever and still crash to the desktop in 3/5 games that you try to play 10 minutes of.

In the Powercolor MYST situation, the cooling solution simply isn't good enough to handle that much heat even though it works fine under all gaming scenarios. What you're seeing is the same thing that I saw on my review sample early this year when I was BTC mining on it around 1250mhz.
 
I've just replaced my 7870 myst with two 7950s, but I did a fair bit of experimenting with it over the 10 months I had it. I've got a few suggestions.

--Before even bothering with the points below, make sure you are running either version 032 or 028 of the vbios for this card. If you have 031 or 030 then please update you bios to 032. Check this in gpu z, the vbios version will look like: 015.xxx.000.000.000000 The xxx are the three numbers I am talking about (032/031/028 etc.) If you have a version above 032 then it is newer and may be better, I haven't seen anything past 032--

Once you have got a bios 028 or 032 I suggest:

1. Don't bother running furmark/kombuster with this card. It will drill your gpu more than it does with other cards. I am not sure if this is because of unoptimised powerplay/tdp/other-things-i-dont-understand settings or what. I think it is most likely because of the next point I am going to bring up:

2. The stock voltage on these cards is too high. I didn't bother doing a lot of testing with this because 1 of the first 2 values I tried worked perfectly. Stock voltage is 1.256 volts I think. I dropped it to 1.2v and was still able to achieve an OC of 1200mhz on the core. Performance actually increased slightly at 1200mhz 1.2v compared to 1200mhz 1.256v. This may not be so important to you because you have an aftermarket cooler, but using the stock cooler I dropped my temps from nearly 90 when overclocked in games to almost 10 degrees lower. Use a program called VBE7 to do it because I couldn't get voltage unlocked with AB on this card. You can try lower voltages, I know for me 1.15v didn't work, but I am sure some value in between would work. I didn't optimise this as I only found out the voltage was too high just before I got my 7950s and 1.2v worked well enough.

3. The VRMs get fkn hot. This is solved by lowering the voltage above, or if you have a cooler with good VRM cooling installed. Mine dropped from well over 90 deg to under 80 with just the voltage adjustment


Besides number 1, these suggestions might not be as useful to you with since you have an aftermarket cooler. I would still suggest giving it a go because if kombustor can do that two your temps then there is the potential that a certain game might make your card behave similarly. It's unlikely that anyone would code a game to try to kill your card like kombustor does, but it is possible.

After you try lowering the voltage you can try kombustor again, but honestly mate, it's a useless program.


I can send you a copy of my undervolted bios if you would like, but I would suggest just downloading it and using the editor I linked to. You can change things like fan curve to your liking. The program is the simplest of tools, it literally just asks you to enter the values you want for voltage(vddc) clock speed etc. You don't have to change anything other than voltage if you don't want.
 
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And please if other users stumble across this, give it a go. Especially those using the stock coolerThe card is awesome price/performance wise and you can mitigate some of the bad caused by the crap cooler by following the above. My core temps are were much lower even with 20% less fan speed and for me it was rock stable. My VRMs are no longer glowing red either:p

If you need any help just post here and pm me, I'm lurking a fair bit

PS. I think you can use Trixx to lower the voltage also, but for me it didn't stick well, and wouldn't go into lower power states. You could use trixx to find a stable voltage before editing the bios to that value, perhaps though.
 
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Thanks picket and david. I flashed to 28 as soon as I got the card. My vrms are actually getting some airflow from my cooler. I was also looking for a bios editor too (used to use rbe on my 6870 + 6850) so ill try your suggestion (my voltage hovers around 1.223 - 1.233)
 
Yeah voltage droops a bit under load, mine were reported about there too. I'm pretty sure there all set at 1.256v in the bios from what I read. If you set it to 1.2v it will droop lower still. Anyway, just suggestions if you are still not happy with temps. Your core temps are way better than mine were with stock cooler so if your vrms are better also, then I guess you haven't got much too worry about anyway!
Mainly I was just hoping my post helps others. I didn't realise how much better the card could be even with the stock cooler until I heard about the voltage being to high and tried out vbe7 for myself. That only happened last week so I haven't got around to sharing it, so I thought I'd take this opportunity.
 
I was just wondering since you guys have experience with these Myst cards. Do you think a i3-3220 or fx-6350 would bottleneck if i were to run two of these mysts cards in crossfire? Sorry for being offtopic and thanks.
 
Update : Incredible, simply incredible. So I edited the bios, matched up core clock #6 and #0 (1150/1500), dropped the voltage, and adjusted my fan preset. In Kombustor temps still rise past 90c but it takes longer than it did before (before it took ~30 seconds, now it takes around 5+ minutes) and hover around 92-93.

In game temperatures are astoundingly better. Now temps dont break past 65-66c through gaming, benchmarks, etc. And I don't even have to set my power control settings!

Thank you so much picket

kushdawg007 said:
I was just wondering since you guys have experience with these Myst cards. Do you think a i3-3220 or fx-6350 would bottleneck if i were to run two of these mysts cards in crossfire? Sorry for being offtopic and thanks.
Click to expand...

I actually had my i3-3220 last week with my 7870xt (just one). I moved the video card to a i5-2500k and when playing BF3 noticed a improvement in smoothness (im assuming since 4 cores vs 2) over my i3-3220. Granted the i5 was overclocked to 4ghz, but I just felt that the 7870xt didnt balance well with my i3-3220 (my opinion of course)

For you, if the game is going to use more than two cpu cores, then yes, a i3-3220 is going to bottleneck regardless of the video card.
 
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Cool man! If they spent more time tweaking and a bit more effort marketing this card, it would have been one of the biggest hits this year I reckon. I was gaming for a few weeks at 1440p and it was doing an admirable job. Games like BL2 I could play absolutely maxed including AA at 1440. Wasn't quite where you would want it in others, but pretty fkn close for a card that cost $220 or so on release.. I was very impressed. You wouldn't have been able to get the same results on a 660ti which cost about 40% more $$ (In Australia).

Profit margins were probably a bit low on them to want to sell too many heh.
 
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