Power, temps and noise
Performance benchmarks show that the GTX 670 TOP performs much like a GTX 680, and it does so while consuming a little less power. Compare its power-draw against the twin GTX 560 TOPs, as we've done, and you'll see the performance-per-watt strides made by NVIDIA from one generation to the next.
GTX 670 TOP's heatsink isn't quite as massive as the GTX 680 version's. Still, temps are good, very good, for a premium card.
And it leads the noise stakes. We'd go so far as to call it whisper-quiet in full-blown 3D mode.
