GTX 560 Ti vs GTX 570?

Forget synthetic Passmark rankings or guesses from HWCompare ( their numbers are purely theoretical, based upon the manufacture's specs- not based upon any actual testing of the cards)

Look at how they compare in actual games:
http://www.bit-tech.net/hardware/2011/11/10/battlefield-3-technical-analysis/4
http://www.tomshardware.com/reviews/geforce-gtx-560-ti-448-core-benchmark,3082-4.html
http://www.techpowerup.com/reviews/AMD/HD_7850_HD_7870/7.html

The GTX 560 Ti isn't bad for the price, but the 570 is unquestionably more powerful.

Since the GTX 560 Ti sells for about $235 versus $280 for GTX 570, I think it's worth going higher-end if your power supply can handle it.

Don't pay over $250 for a 570, or $200 for a 560 Ti.
I think you're better off buying a used 570 for around $200.

560 Ti vs 570 http://www.anandtech.com/bench/Product/547?vs=518

The GTX 560 Ti is definitely worthy of your attention with a good price at around $ 220 to 250 on Newegg, which is the card I own, but of course the 570 is higher performance than the 560 ti, but just with a little more power draw. Honestly, if you are on a tight budget, the 560 ti should more than suffice as an upgrade, but if you can afford the higher cards, then by all means go for it! :)

The gtx 560 ti is a changed version of the gtx 560 and between the bottom graphiccard which could run BF3 at medium to extreme settings with reliable specs, the gtx 570 is a dazzling card for gaming again with reliable specs and could upward thrust as a lot as extremely settings on some video games with reliable fps

A 560 will certainly provide better than 50% of the 570's performance despite costing about that much less.