The GeForce GTX 660 also sports lower clock speeds. The card has an 823MHz base clock and an 888MHz boost rate, both down about 100MHz from the Ti. The memory clock is slower, as well. Nvidia quotes a 5.8 GT/s memory transfer rate, which is a drop of 200 MT/s. Although the OEM variant's memory interface width remains 192 bits wide, cards will be available with 1.5 or 3GB of onboard memory rather than the 2GB found on the Ti.
The GTX 660 Ti has a maximum power rating of 150W and requires dual 6-pin PCIe power connectors, but the OEM flavor is rated for 130W and demands just one PCIe power lead.