This new Ti will, if VR-Zone is right, be based on the GF110 chip, which makes it a close relative to the 570 and 580 models. It will also mean a drop of the current GF114.
The publication reports that the new 560 Ti will essentially be a 570 with 14 (and one disabled) streaming multiprocessor with a total of 448 cores, up from the current 384. It is more than likely that the clock speed will be below that of the 570. Expect to see the 320-bit memory interface with 56 TMUs and 40 ROPs.
The likely performance gain is pure speculation at this time, but I will make an educated guess that the card will be consuming more power than the 170 W of the current 560 Ti and move closer to the 219 W of the 570.
Current 560 Ti graphics cards sell for street prices in the $220 to $270 range. An upgrade could breath more life into the card, which should help Nvidia move more chips during the upcoming Christmas season.