depends on your budget
importand is don`t take the reference cooler(exhaust system)
because they are insane loud
if you wanna do an apple for apple comparison with the next gpu architecture compare yourself these raw compu specs aka silicum
GeForce GTX 650 Ti 2GB vs GeForce GTX 660 Ti
Intro
The GeForce GTX 650 Ti 2GB comes with a core clock speed of 928 MHz and a GDDR5 memory speed of 1350 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is made up of 768 SPUs, 64 TAUs, and 16 Raster Operation Units.
Compare all of that to the GeForce GTX 660 Ti, which comes with GPU clock speed of 915 MHz, and 2048 MB of GDDR5 memory running at 1500 MHz through a 192-bit bus. It also is made up of 1344 SPUs, 112 Texture Address Units, and 24 Raster Operation Units.
now because the nvidia is kepler architecture(previous fermi nvidia`s nuclear option)
and was build for more performance per watt
i add the 550 vs 650
The GeForce GTX 560 Ti uses a 40 nm design. nVidia has clocked the core frequency at 822 MHz. The GDDR5 memory works at a speed of 1002 MHz on this card. It features 384 SPUs along with 64 Texture Address Units and 32 ROPs.
Compare those specifications to the GeForce GTX 650 Ti, which comes with a GPU core clock speed of 928 MHz, and 1024 MB of GDDR5 RAM running at 1350 MHz through a 128-bit bus. It also features 768 SPUs, 64 Texture Address Units, and 16 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
GeForce GTX 650 Ti 110 Watts
GeForce GTX 560 Ti 170 Watts
Difference: 60 Watts (55%)
Memory Bandwidth
Theoretically, the GeForce GTX 560 Ti should perform much faster than the GeForce GTX 650 Ti in general. (explain)
GeForce GTX 560 Ti 128256 MB/sec
GeForce GTX 650 Ti 86400 MB/sec
Difference: 41856 (48%)
Texel Rate
The GeForce GTX 650 Ti should be a small bit (about 13%) more effective at anisotropic filtering than the GeForce GTX 560 Ti. (explain)
GeForce GTX 650 Ti 59392 Mtexels/sec
GeForce GTX 560 Ti 52608 Mtexels/sec
Difference: 6784 (13%)
Pixel Rate
If running with a high screen resolution is important to you, then the GeForce GTX 560 Ti is the winner, by far. (explain)
GeForce GTX 560 Ti 26304 Mpixels/sec
GeForce GTX 650 Ti 14848 Mpixels/sec
Difference: 11456 (77%)
Power Consumption (Max TDP)
GeForce GTX 650 Ti 2GB 110 Watts
GeForce GTX 660 Ti 150 Watts
Difference: 40 Watts (36%)
Memory Bandwidth
Theoretically speaking, the GeForce GTX 660 Ti will be 67% faster than the GeForce GTX 650 Ti 2GB in general, due to its greater bandwidth. (explain)
GeForce GTX 660 Ti 144000 MB/sec
GeForce GTX 650 Ti 2GB 86400 MB/sec
Difference: 57600 (67%)
Texel Rate
The GeForce GTX 660 Ti will be quite a bit (more or less 73%) better at anisotropic filtering than the GeForce GTX 650 Ti 2GB. (explain)
GeForce GTX 660 Ti 102480 Mtexels/sec
GeForce GTX 650 Ti 2GB 59392 Mtexels/sec
Difference: 43088 (73%)
Pixel Rate
If using high levels of AA is important to you, then the GeForce GTX 660 Ti is the winner, by a large margin. (explain)
GeForce GTX 660 Ti 21960 Mpixels/sec
GeForce GTX 650 Ti 2GB 14848 Mpixels/sec
Difference: 7112 (48%)
on nvidia fermi gpu`s the shader clock is double the core clock that`s one of the reasons to explain this difference