GeForce GTX 660 Ti Twin Frozr 3GB Edition is a special edition of GeForce GTX 660 Ti.
The new features include the Twin Frozr III Thermal Design which is 25ºC cooler and 16.9 dB quieter than reference design, according to MSI. In terms of overclocking, the base-clock was increased from 915MHz to 967MHz and the boost clock can now reach 1046MHz, instead of 980MHz. The memory clock was left untouched but the frame buffer was increased to 3GB which actually reduces the performance due to the 192-bit bus width not being to handle the 3GB efficiently.
The overclocking is somewhat relevant and benchmarks indicate the performance boost is around 1% when compared to standard GeForce GTX 660 Ti.