Hi there im currently looking for a new graphics card. My choices are:
1) Zotac GTX460 1GB
2) ATI HD5870 1GGB
3) Sapphire 5850 1GB
Now im looking for the best gaming one in DX11, and in DX10. And the best one if i thought of SLI or Crossfire in the future?
ECS p55h-a motherboard
Intel Core i3 530
Kingston Hyper X DDR3 1800mhz 4GB
19" Moniter (1440x900)
For that resolution? The 5870 would be your best bet for raw performance, but really a 5770 would do just as well, probably. It's a significantly lower resolution than the 1080p HD (1920x1080) those cards are meant to perform at.
Your current motherboard can not support SLI OR Crossfire (only one PCI-e slot), so you'd have to get a new one, but again, the 5870 is the best choice there by a wide margin (5850 < 460 << 5870). With your current monitor, though... I'd almost recommend you stick with a single 460 now, get a new monitor as your next tech purchase (1920x1080 resolution for the new one), and a SLI 460 setup will run the new resolution just fine.
and last years fastest GPU was? and wouldnt gtx 460 SLI be a good option?
Last year's fastest GPU is the 5870. I said that...
And yes, GTX 460 SLI is a good option, but for that matter you could get a Radeon 6870 for cheaper than a 460 which, while about the same as a 460 alone, is better in Crossfire than the 460 SLI setup.
But the 5870 Crossfire is the most powerful setup you can get nowadays (more powerful than the 460 SLI, yes), with the exception of a 6970 Crossfire or a 570/580 SLI. And again, just stick with Crossfiring, it's not worth the headaches.
The 5870 SHOULD cost about $200 right now, same as the 460, so there's no reason whatsoever to get a 460 over it.
This is not to mention that PhysX only really shines when you can dedicate a secondary (or tertiary in SLI setups) Nvidia GPU to doing the work. When you try to run it using the main display card, you get staggering blows to framerate -- perhaps not as much as trying to do CPU PhysX, but still quite a bit. Combining that with the fact that it's in relatively few games (and its effects are only readily apparent in a fraction of those), and the 5870 edges out ahead.
And remember that the SLI hack is not a 100% stable operation, you probably will never get as much performance out of a hacked SLI mobo as you would just using one designed for it.
460s beat the 5870s in the one case of a tri-monitor setup. As opposed to my link, where 5870s outright beat the 460 at any given single-monitor resolution, and since OP hasn't indicated he plans to get 3 monitors in the future, the 5870 wins.