Listen people
GTX 470 beat a 5850 but costs the same/more than a 5870
GTX 480 beats a 5870 but costs almost as much as a 5970 and is not as good as a 5970.
Solved.
What do I win?
One minor fix, the 5850 will overclock past the speed the 480 can achieve, on the stock cooler quieter than a stock 470gtx, and neither the 470/480gtx will likely get close with overclocking.
1Ghz is achievable but seemingly rare and not with silence on a stock cooled 5850. 925 is very easy, thats over a 25% overclock, hit 975and you're at about 35% overclock, the few that can hit 1Ghz, will have a 40% overclock.
The few overclocking tests I've seen suggest maybe a 10% overclock, eek that out to 15% with voltage control IF there is voltage control, it won't come close.
Thats the big problem, the 5850 has HUGE headroom, I mean huge, and anything this generation but a 5850 is a daft buy, be that 5870, 5970(at current prices, at £430rrp its still a choice but frankly 2x 5850's would overclock better and be easier to cool), 470gtx, 480gtx, or a likely 460gtx.
The 5850 is the single most obvious choice between gpu's in the high end market, in the past decade frankly.
After the 4870 was released, the 260gtx 216 version came out and it was priced not far off a 4870, either would give you great performance at competitive prices, you'd not be dissappointed with either.
THis gen, theres nothing close in price/performance to the 5850 and unlike last gen, the 5850 can produce top end performance, where the 4850 could not replicate 4870 performance under any circumstances.