I'm snooping around for a deal on a video card - I'm not a heavy enough gamer to justify paying £120 for a 4850 (bargain that it is), so I'm watching for cheap last generation cards appearing on the market (eBay etc.) as folks upgrade.
I've checked the benchmarks for games at 1600x1200 (my native resolution) for games that have been out a little while (PC games depreciate fast, and I'm a patient man), and the 4850 is around 30-50% better than the 3870/8800 GT/9600GT, and approaching 100% v the 3850.
Other considerations are warranty (could you feasibly get one on a used product?), power consumption and noise.
Lastly, would I be better served waiting for a 4650 or 4670?
On a pure performance basis and buying new, I'd estimate their real value at:
£90 - 8800 GT 512mb
£80 - HD 3870 or 9600 GT
£65 - HD 3850 512Mb
£60 - HD 3850 256Mb
Completed listings (inc. P&P) on eBay suggest:
£70-£80 - 8800 GT 512Mb
£60-ish - HD 3870
<£50 HD - 3850
My feeling is if I got something on eBay going for below those completed listings prices (esp. the 3870), I'd be doing well. I'm interested to hear some opinions, though.