Yes, definitely. Even if you had PCI-E v1.2 slot it would work. 660ti is a great card.
GeForce GTX 660 Ti is a high-end GFX based on the 28nm, Kepler architecture.
It's based on the Kepler GK104 Core and offers 1344 Shader Processing Units, 112 TMUs and 24 ROPs, on a 192-bit memory interface of fast GDDR5. The central unit runs at 915MHz (up to 980MHz in Turbo Boost) and the memory clock operates at 1502MHz.
Compared to GeForce GTX 670, it offers 25% less memory bandwidth, resultant from the 192-bit bus (against the 256-bit of GeForce GTX 670) and offers 8 less ROPs - a consequence from featuring 25% less memory bandwidth (as they are not needed).
The more image improving techniques used (e.g. MSAA) and the higher the gaming resolution, the lower GeForce GTX 660 Ti's performance when compared to GeForce GTX 670.
Note: 3GB versions of this GPU are expected to perform worse, even at modest resolutions, due to the 192-bit bus width not being to handle the 3GB efficiently.