What does worth mean to you? To me it means having a higher percentage improvement per dollar, and the fact is, getting a third card is cheaper than what little you get selling them and then spending several hundred more while only gaining a few more frame rates.
For instance,
this is a guru3d review of 2-way and 3-way SLI GTX670 scaling, and
this is a review by benchmarkextreme of 2-way and 3-way SLI GTX570 scaling. It clearly shows that at 2560x1600 in the game Metro 2033, 3-way SLI GTX570 would generate 58 frames per second while 2-way SLI GTX670 nets 65 frame rates. While the GTX570 has 1280MB and the GTX670 ref has 2048MB, the frame rates didn't scale with having more Vram; so even if you got the 4GB model, your rates aren't going to scale up that much more. 65 against 58 is a
12% improvement; for about £140 getting a third GTX570 is way cheaper than spending hundreds more for so little short-term gain on a pair of 670's.
That is of course if you are playing Metro 2033, if not choose another game common in both reviews and you will see a different score pattern. If you plan to keep your next upgrade longer than the two years GTX570 has been around, then only would I suggest getting the higher Vram models of newer cards against reference. nVidia has done their homework, they know what most people want, thus why the 2GB models are reference.
Enthusiasts are not most people; although some assume if enthusiasts buy high-end then all high-end are enthusiasts, that is a logical fallacy. Just so you know, many active members of this forum simply cannot stand recommending what they regard as old stuff simply because they have made the choice to keep up with technology; they don't think about other people. Try not to get haggled by them to change based on
their preferences because this is your system and your money. But you're more than welcome to change if you want to, it will certainly show you what percentage gain is worth your money, i.e. what you're willing to change for.
As for power, each
GTX670 draws as much power as a
GTX560 Ti = 170W max board, compared to
GTX570 at 219W max board, you won't need to upgrade the PSU unless it is very old (close to or past warranty).
post edited by lehpron - 2012/11/22 10:20:09