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How to overclock a 7850 past 1050MHz?
- Thread starter 555BUK
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![[timko]](/styles/overclockers/avatars/5.png){kind=avatar}
PowerTune doesn't work by dynamically adjusting the voltage (you can verify this yourself with monitoring software like MSI Afterburner) to obtain a set TDP. Since AMD do not reveal the exact formula they use to calculate what needs to be adjusted in order to reach target levels, it's up to the more technically minded among the general public have a guess at. Ryan Smith of Anandtech.com gives his take on it during the 6950/70 release of Dec 2010...
http://www.anandtech.com/show/4061/amds-radeon-hd-6970-radeon-hd-6950/7
http://www.anandtech.com/show/4061/amds-radeon-hd-6970-radeon-hd-6950/8
[timko];21798698 said:
so are you saying that CCC IS adjusting my voltage (based on some formula)? i tried to clock up to 1225mhz, which i would suspect would require more than 1.176v, and the max voltage stayed right at 1.176, so i'm pretty confused as that indicates CCC is not adjusting the voltage at all.
back with my new 7850, had to get the OC version since they didnt have the normal version in store,didnt want to wait a week or 2 to order so i paid the difference.
and now i discovered that my psu is faulty...(crackles occasionally and whines when i move the cursor)
and now i discovered that my psu is faulty...(crackles occasionally and whines when i move the cursor)
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You sure it's your PSU, and not your new card?
Here's my first sentence again...
[timko];21798698 said:
Plus you've already confirmed the second part of my sentence by noting that the voltage doesn't change
The second link I gave above at Anandtech really does cover it in good depth so please have a read of it if you only have time to read one of them
Just gotta wait til I get my IB delivery tomorrow and I'll post up my own OC results. Can't wait Some time ago ATI introduced memory error correction routines on their cards, meaning that instead of going all BSOD, producing artifacts or crashing the display driver, the card will quietly repeat failed actions multiple times until it works. What this means in practice is that at some point in your overclocking you will actually start to lose performance even though the card seems stable at the higher clock, this is why running benchmarks is much more important nowadays to see whether the performance gains are legitimate. You need to find the sweetspot, the highest balance between memory and core overclocks before them routines kick in (core clock being the more valuable of the 2), start by keeping the core and reducing memory.
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Would this be anything like slackening off memory timings?
Yeah, the stock cooler on mine only allowed for benching at 1315Mhz and full stability at 1275MHz.
It's not the size of your cooler, rather GPU quality that counts most, and GPU quality is pot luck. If however you need quieter running and the potential for an extra 10-20MHz, a bigger cooler will help.
Is a custom cooler worth an extra ~£40 (~20%)? I would say no, but others will ague.
Well, we have to work with what we have easy access to which is the memory clock alone in this case. It is a bit of an awkward comparison but I suppose we much rather reduce the memory clock on the GPU while keeping the core clock as high as it will go, not unlike trying to loosen timings a bit on RAM before giving up on the desired clock.
As overclockers, we should see the error correction routines as an annoying and deceptive innovation that only serves to hide the very real instability at the cost of performance.
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What do you guys think of the XFX?
http://www.neoseeker.com/Articles/Hardware/Reviews/XFX_R7870_BE/
Its 30 euro more expensive then the sapphire one but i think its based on the 7870 PCB well looking online thats what im seeing.
Would the 7850's PCB on the Sapphire be a better overclock then the XFX's 7870 PCB on their 7850?
Any ideas?
http://www.neoseeker.com/Articles/Hardware/Reviews/XFX_R7870_BE/
Its 30 euro more expensive then the sapphire one but i think its based on the 7870 PCB well looking online thats what im seeing.
Would the 7850's PCB on the Sapphire be a better overclock then the XFX's 7870 PCB on their 7850?
Any ideas?
7870 PCB is a non-issue imho. It all comes down to the quality of the GPU core. As you can see in this thread, as long as the core is good you're going to get 1200+ on a normal 7850 PCB. A bad core isn't suddenly going to OC better just because its on a 7870 PCB.
Best card atm is the £185 HIS 7850. Great price, custom cooler, and 2yr warranty direct with OCUK.
Best card atm is the £185 HIS 7850. Great price, custom cooler, and 2yr warranty direct with OCUK.
