So I just upgraded from a Gigabyte windforce GTX 660ti 2GB OC edition card to the Gigabyte windforce 3x GTX 770 OC 4GB. I gave my GTX660ti to my little brother as a gift, and he gave me in return his card. An zotac GTX450 768mb version, Now before I even try, will this card just slow down my physX(saw a test on youtube), or would it actually be worth trying to see if the PhysX games runs better.
Depends on if the game uses GPU acceleration. Many don't. Did u use the 660 for Physx after buying a 770?
Gerardfraser who's also a member here ran a few benchmarks with a 680 and a 450: http://physxinfo.com/forum/index.php/topic,180.0.html You should see an increase in performance.
A 560 with a 670 makes almost no difference in my experience. It can be up to around 10% faster in some circumstances, but those circumstances are few and far between. I gave up on the idea entirely when I switched to a 780 and the 560 now sits in the cupboard as a backup card in case things go horribly wrong (the 670 is in my old machine pending being sold). Being that a 450 is slower than a 560, and a 770 is faster than a 670, the difference will be practically nothing - unless you're grinding the 770 into the dirt with rendering duties (ie 30fps or less).
