Ive been looking at purchasing a HD6870 for a build, and was wondering is it worth buying a factory overclocked GPU, or should i Just buy the standard Card and do it myself. By the way im quite new to overclocking so would have to learn haha.
Also, is there a perticular make i should be going for with graphics cards?
As always there is a "it depends" here. It used to be that the stock cards could most of the time be bumped up to as fast and usually faster actually than the factory over clocked cards. The thing that has to be considered is that although its much less likely these days it is possible to get a stock card that just plain wont OC as far as the factory card or just not OC at all.
These days the niche thing seems to be upping voltages to get more stable or higher clocks, some of the stock cards don't support this so you would need a non reference card if this was something you wanted to do. The Asus CU cards are good for this as well as the MSI Hawk design which is basically built to Overclock using much better circuitry and components than a stock card and also better more robust power regulation .
Normally it would be fine to get a standard card and overclock yourself. The issue is with the 6870, which is known to have relatively little headroom for overclocking. Better to get a factory overclocked one, so you get the guaranteed overclock, then overclock from there. Hopefully, a factory overclocked model will also have better components and higher chip binning to allow for higher overclocks than you could get with a standard version.