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7950 DD overclock - my limit?

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February 27, 2013 4:56:00 PM

Hey guys,

So the core clock is 800MHz and memory clock 1250MHz on this card.

Using MSI AB I slowly raised the Core clock and Memory clock (not touched voltages or power limits) by 30MHz each time, then did some GPU burn tests in FurMark and Heaven Benchmark etc.

I got to 900MHz and 1350MHz, and it ran fine, temps were ok, FPS went up a bit in the tests and so on. Was averaging about 53 FPS on both tests.

So I tried to raise more (after reading about people getting higher overclocks comfortably), and went up again 30MHz in each.

Furmark results seemed right, a few more FPS, a little raise in temps etc.
I then ran Heaven Benchmark and it crashed, tried it again and crashed again. so i went back to my stable settings and it worked again.

Next day i tried going up in 20MHz, so 920MHz and 1370MHz, Heaven ran fine, this time FurMark was showing strange results, FPS average was about 30FPS, so quite a drop.

I have since read many articles, and tried a few other things, like not raising the memory clock so much, but results seem random, like I say sometimes one test is fine, and the other shows strange results. One time I thought I cracked it, both were working fine and temps fine etc., then in battlefield 3 I got a weird crash, my gun kind of went all weird, it was almost liek someone had mounted a massive shield on my gun, then it froze and i got message saying my AMD card has stopped working and recovered... can only think this way because of the OC.

So anyway im back to 900, 1350 now and all is good... do you think this is my max settings and I should stick with it?
Could just be a case of I need to up the core voltage to get further results, but I don't know if I am comfortable going down that road.

More about : 7950 overclock limit

a b K Overclocking
February 27, 2013 9:42:12 PM

That is usually an indicator that those settings are not perfectly stable and probably require more voltage. If you don't want to add voltage stick with your 900/1350 overclock settings. If you wanna push those boundaries though, you're gonna have to add voltage.

Hope this helps ;) 
February 28, 2013 7:31:12 AM

Cheers buddy.

The volts is greyed out in MSI AB, and cant see the voltage settings in CCC.

I think there is a way to get it to work in MSI AB though, something about editing a file and changing a value from '0' to '1' or something. Might have to look into that...

Is the volts similar to Core and Memory clock, as in go up slowly etc?
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a c 147 U Graphics card
a b K Overclocking
February 28, 2013 8:51:27 AM

Stay at 900/1350.

When you severely overclock you also risk killing your card and your fan noise will jump up significantly as the heat rises.

Furmark:
When your performance dropped dramatically it's likely because you hit such a high GPU temperature that the card forced itself to run at idle frequency as a safety measure.

Rather than risking the card to get an extra 3FPS, keep at a fairly safe overclock and concentrate on tweaking games for optimal performance. If you can't hit 60FPS (VSYNC'd) then adjust Anti-Aliasing, Shadows etc for the best compromise. Most games should run at 60FPS with max quality or close to it. (Far Cry 3 is a big exception which I'm hoping gets another patch. Without VSYNC there's severe tearing but with it most cards can't hit 60FPS so it auto resynchs to 30FPS instead. Sigh).
a b U Graphics card
a b K Overclocking
February 28, 2013 9:13:14 AM

be careful, you might end up with less if you push too much
February 28, 2013 1:58:29 PM

photonboy said:
Stay at 900/1350.

When you severely overclock you also risk killing your card and your fan noise will jump up significantly as the heat rises.

Furmark:
When your performance dropped dramatically it's likely because you hit such a high GPU temperature that the card forced itself to run at idle frequency as a safety measure.

Rather than risking the card to get an extra 3FPS, keep at a fairly safe overclock and concentrate on tweaking games for optimal performance. If you can't hit 60FPS (VSYNC'd) then adjust Anti-Aliasing, Shadows etc for the best compromise. Most games should run at 60FPS with max quality or close to it. (Far Cry 3 is a big exception which I'm hoping gets another patch. Without VSYNC there's severe tearing but with it most cards can't hit 60FPS so it auto resynchs to 30FPS instead. Sigh).


Thanks for the reply

Regarding Furmark, strange thing is, when I did the burn test say a week ago, i was getting about 52 FPS and about 72 temps. that was at my stable settings, I then upped my benchmark and the fps dropped... so i went back to my safe stable settings, and fps was still showing low, about 30 odd, it started at about 57FPS then constantly dropped to about 32.

Could just be because my GPU was hot, as I ran a few stress tests etc?

Will try again tonight (at my safe OC settings)
a c 147 U Graphics card
a b K Overclocking
March 1, 2013 6:52:16 AM

ohh_danielson said:
Thanks for the reply

Regarding Furmark, strange thing is, when I did the burn test say a week ago, i was getting about 52 FPS and about 72 temps. that was at my stable settings, I then upped my benchmark and the fps dropped... so i went back to my safe stable settings, and fps was still showing low, about 30 odd, it started at about 57FPS then constantly dropped to about 32.

Could just be because my GPU was hot, as I ran a few stress tests etc?

Will try again tonight (at my safe OC settings)


FURMARK is very demanding and has actually killed many cards in the past. I'm not completely sure how your card protects itself.

The frequency they choose for a graphics card (i.e. 900MHz) is chosen based on a worst-case scenario for games to prevent overheating and crashing. Furmark is an artificial scenario that stresses a card more than the design intends.

This entire concept is why "GPU BOOST" was created (AMD has a similar feature now on some HD7000 cards). Since games stress cards differently the shift is now to figure out the TEMPERATURE a chip can handle and adjust the frequency dynamically.

In addition I think all modern cards can now downclock to Idle speeds to protect themselves but I'm not completely certain.
March 1, 2013 4:37:55 PM

Had a good play around with the core, memory and voltages last night.

It seemed I could up the core to about 1000 and memory to about 1450, and up the voltage to about 1050 and heaven benchmark was fine. Running Heaven on my default settings (800, 1250) got about 45FPS, on last nights settings got around 55FPS...

But ... FURMARK still showed low fps, on default card settings it read about 30 fps, on last nights settings it got about 40FPS, but it's strange as before 900/1350 got my 50+ FPS! So I thought maybe the OC was unstable so went back to 900/1350, and it was about 33-35 FPS.

So I've lost faith with FURMARK tbh, readings seem too inconsistent.

I have gone back to my safe settings (900,1350) and not upped vaults.

I think I will stay with these until games really push my system! Then ill look at other benchmarks and go from there.
a c 147 U Graphics card
a b K Overclocking
March 2, 2013 3:16:47 PM

ohh_danielson said:
Had a good play around with the core, memory and voltages last night.

It seemed I could up the core to about 1000 and memory to about 1450, and up the voltage to about 1050 and heaven benchmark was fine. Running Heaven on my default settings (800, 1250) got about 45FPS, on last nights settings got around 55FPS...

But ... FURMARK still showed low fps, on default card settings it read about 30 fps, on last nights settings it got about 40FPS, but it's strange as before 900/1350 got my 50+ FPS! So I thought maybe the OC was unstable so went back to 900/1350, and it was about 33-35 FPS.

So I've lost faith with FURMARK tbh, readings seem too inconsistent.

I have gone back to my safe settings (900,1350) and not upped vaults.

I think I will stay with these until games really push my system! Then ill look at other benchmarks and go from there.


Fur Mark isn't a good choice for a benchmark anyway. It's a SPECIFIC benchmark that also overheats the card.

It really only matters how your games are performing. If you want to buy a new card, then simply look online at benchmarks for new cards relative to your existing card.
April 13, 2013 4:28:51 AM

i hit 950/1400 core/mem on my XFX R7950DD (non black edition) with 1.090 VDDC stable as far as it goes (on stock VDDC i have random crash)
!