> AMD OR NVIDIA WHICH IS GOOD
Both are great. > I LIKE NVIDIA BECAUSE OF PHYSICS,REALISM
If you want realism then buy a top tier AMD card. Realism isn't an nVidia vs AMD thing.
As for physics, that's like buying a specific yacht because they serve good martinis in the bar.. Which may be a good reason to buy a yacht, I don't know, never bought a yacht. Anyways hardware Physx doesn't improve game play, it improves the debris/sparks and such in the few places in the few games that support it. Will it make your game better? No, you wouldn't notice it if you weren't looking for it. No. no dedicated Physx for you. > should i buy hd 6670 or 6770?
I'd get the 6770. AMD's site says it will run on a 450w psu. Check their site for it.
This site shows power reqs:http://www.hwcompare.com/8115/geforce-gtx-460-vs-radeon-hd-6770/
If your psu is good then you'll be ok. If your psu is not then who knows. I had a 460 watt psu that ran my vid card fine but after a year the system started to brown out so I grabbed a used 350w, shoved it in to my cd drive bay and tied the signal on pins together and moved my my drives / fans to it and then everything was happy again.
Good luck in your upgrade.