Hot on the heels of the GTX660Ti's release NVIDIA have uploaded the specs of an OEM version of the anticipated mid-range GTX660, and it makes for quite interesting reading. The specs are (as you might expect) some way down on the Ti version, yet high enough that it should give AMD 7850 and 7870's a run for their money in most benchmarks.
Key to the anticipated speed of the GTX660 is the fact that it appears to use a 28nm Kepler-based GK104 GPU, albeit a salvaged version with fewer active CUDA cores than other Kepler SKUs. That's the same GPU as the 660Ti, as well as the 670 and 680, whilst the binning of this GPU means that it will ship with only 1152 CUDA cores enabled (down from 1344 in the 660Ti and 670). The GPU is clocked at a modest 823MHz, down from 915MHz on the 660Ti, but with GPU Boost enabled will clock up to 888MHz. Going purely from GPU spec that's not an inconsiderable drop in theoretical performance, close to 25%.
On the memory side, the memory bus width is as wide as that of the 660Ti - 192 bit; however the frequency will be ~5800MHz rather than the 6008MHz seen on desktop Kepler-based VGA cards thus far. Do doubt this will allow OEMs to save a little on expensive GDDR5 RAM, of which the GTX660 will have 1.5 or 3GB. Again, that will have a knock-on impact on the performance of the card relative to other Kepler-based desktop cards.
Coming as standard will be DVI/D, DVI/I, HDMI and DisplayPort connections, probably allowing up to four displays (though Surround and 3D gaming may be asking a little much of the card). Power requirements are very modest at only 130W, and correspondingly the card will be fitted with a single 6-Pin PCI-E connector.
It's worth noting that these are reference specs for an OEM version of the GTX660, and may vary from the version AIB's eventually ship with. That said, given the way previous desktop-class Kepler SKUs have shaved parts off the GK104 for specific performance levels, it doesn't seem inconceivable that a retail GTX660 would only vary by core and memory frequencies. However conflicting reports have emerged of a GK106 being the basis of the GTX660 (see: WCCFTECH), though initial rumours speculating that it would have only 768 CUDA cores make this assertion difficult to give credence to.
Not all that long ago, a simple vBIOS update would have been able to unlock some of those disabled shaders. Oh well...