ATI 4850/4870 voltmod thread

[dejanh]

@dejanh and powercolor card
Well, I've had no problems with my 4870 even on 800/1100 and stock cooler, I just modified BIOS fan tables so I have low fan in 2D and high in 3D and that's it.. And I stay away from Furmark, cos if it runs all games just fine for hours and under 90C VRMs, why the hell would I want to run furmark for over 126C after 30 seconds?
Now I've mounted Accelero S1, and I have to say that manufacturers will have a hard time keeping this card cool with inferior cooling as this Powercolor had. I had S1 and two 120mm fans, and it was still no better under very high load than stock cooler was on 60% fans (except that it was quiet). So I had to mount a higher powered 120mm fan which is not noisy but can be heared even when it's not complete silence in the room, and only now do I have very good temps when not overclocked, and just about the same as stock @60% fan when OCed to 800/1100 and under heay load for an hour or so..

So I don't think that any manufacturer will get this one right. And the reason is not even in GPU speeds but in memory. This GDDR5 draws a lot of current, and it's the number one reason why both VRMs and even GPU heat up. Cos when I clock memory up, "MEMIO" sensor on GPU goes sky-high even with a good cooler like S1+dual fans, and that heats up whole GPU chip a bit.. Also, amps go up a lot, and that heats VRMs. So they can clock the GPUs but I wouldn't recommend anyone clocking memory after everything that I've tried. One more point for that is - this card is really not held back by memory. I'd say it's held by CPU (for anything not clocked over 3.5GHz), than GPU, and only than memory..

So people - for 24/7, just don't clock memory.. no need, and just a bunch of potential problems. Potential, but almost certain..

Agree completely. It is not the stock cards that tend to be problematic, it is the "factory OC" ones that do. Clearly the manufacturers do not really have a good idea of the cooling needed on these cards, especially the VRMs. That's basically what kills them all and exactly what I stated. Indeed, I found that it is the two memory VRMs that get ultra-hot. GPU VRMs get hot as well, but not as much as the memory ones. Keeping memory lower is a good idea. The memory is not a bottleneck for this card and only real benefit from OC comes when you OC the core. The minimum CPU to not cause bottleneck on this card is about 3.6GHz Core 2 (AMDs just are not going to do this ATM). The only thing I disagree on is that in my opinion the card should be able to run anything (including FurMark) without any risk of the card experiencing problems or worse yet frying. Maybe ATI engineering team and their manufacturers should use FurMark to stress their cards