hhmmm, the preformance difference from the 7850 to 7870 is high, so to oc the card to the 7870 will require some serious overclocking but surely if you're willing to clock the 7850 to that extreme, you can apply the same theory to the 7870 which can clocked much further than it's default speed.
In any case i don't plan to overclock my card at the moment, maybe when it gets older.
as i said i haven't been here for a while. do GPUs these days come with their own Overclocking software suites which allow you to change the voltages than compared to the 'bad' old days where you had to flash the bios. if this is so, the OC editions of the cards are effectively useless?
the only good they were before was that they changed the voltages already so you didn't need to flash the bios to achieve higher overclocks.
also only the cheap low quality 7950s are around the £300 mark, sure they all may run the same fps, but fps is not the only preformance criteria; temperature,noise,Bios quality and my favorite resonance. Cheap 5870s squelled like a B***h at high framerate due to low quality components.
Also if anyone can point me to a Reliable source site comparing Oc'ed 7850 & 7870. my internet has became unstable thus speeds to slow to do indepth google search into this.
The 'large' difference between stock 7870's and stock 7850's, comes from the fact 7870's stock clock is higher. This however, doesn't mean the 7870's clock further, and when both cards are at the same clock speed, the difference in performance solely comes from the fact the 7870 has 1280 cores and the 7850 has 1024 cores.
That minor difference equates to very little in games, and considering most 7850's can be OC'ed to match and exceed 7870's stock clocks, at stock voltage, it's really difficult to recommend buying one.
Regarding OC software, you pick which program you want to use, install it, move a few sliders around (voltage, core clock, memory clock), click apply and enjoy the performance boost. Nothing gets flashed to the BIOS AFAIK, all the changes are made in the software and are 100% reversible. And this is another reason why you'd want the 7850 over the 7870.
From what I've read, you literally drag the slider up to 1000MHz, click apply, and you've essentially matched a stock 7870. Again, even though the 7870 starts at 1000MHz, doesn't mean it'll OC further than the 7850, they'll both max out at 1200-1300MHz.
Lastly, in my experience at least, coil whine or 'squeeling' is a really hit-and-miss phenomenon. Just an example of my experience over the years:
LeadTek 8600GT (fairly cheap card) - no whine
XFX 4850 (reference model) - whine
Sapphire 5850 xtreme (cheap, low end version 5850) - no whine
GTX 470 SOC (literally the highest-end GTX 470 you can buy) -
whine
Since then, I've had reference 5850, GTX 570, GTX 480 and 3 5770's, all of which exibited whine when running Kombuster/furmark, but none during gaming or at idle. For this reason, I'd say not buying the cheapest (reference) versions of a card, because you're worried about coil whine, would be a bit silly.
There's a thread on here where someone did the comparisons between a 7850 & 7870 at similar clocks, I'll post back if I find it.
EDIT:
http://forums.overclockers.co.uk/showpost.php?p=21625268&postcount=37
Hope this helps mate
