The card's design is very similar to the 8800 GT with the PCB being exactly the same length, (which itself was the same length as the old GTS) and the layout only differing by way of extra power management circuitry being needed on the 8800 GTS 512. Of course, all the extra processing power of the GTS means it requires a dual-slot cooler to keep from self destructing but rather than using the same design as the previous GTS, nVidia has given the new one a bit of a nip and tuck. OK, perhaps that's a bit misleading as the cooler certainly isn't any slimmer. It is, however, a more ingenious design.
One complaint that has been aimed at dual slot coolers ever since they first appeared is that when used in SLI the back of one card blocks the intake for the fan of the other card resulting in severely sub-optimal airflow and higher than necessary card temperatures. To resolve this nVidia has come up with a superbly simple solution; angle the fan in toward the PCB, creating a larger gap. This isn't the only benefit, though, as the new angle of the fan blows air more directly onto the heatsink surface just above where the G92 chip and its surrounding memory lies, which should help cooling efficiency further.
The vents in the plastic shroud near the PCB end of the card that were present on the old GTS have now been removed, ensuring all the hot air generated by the card is exhausted out the back and not into the case. The shroud now also extends the full length of the card, covering all the power circuitry that was previously exposed, though this seems to be a largely cosmetic change. A little GeForce logo has also found its way onto the top edge of the shroud so it's easy to see what graphics card you have installed - something I'm sure all of us often find ourselves forgetting...
Quite which of these changes has had the largest effect, if indeed there is a significant gain from any of them, is by the by, but what is without doubt is the 8800 GTS 512 is a very quiet and relatively cool card. Even under intense gaming the fan didn't spin up to a disturbing level and for general desktop use it merely idled round.
Likewise power consumption is markedly improved from previous generation cards with it consuming less power than an 8800 GTS 640 both when idle and during intensive gaming sessions. It can't compete with ATI's HD 3870, with its superb PowerPlay technology helping it to cut idle power usage considerably, but it's not a bad effort.
Even though the new card is PCI-E 2.0 compliant it still draws only 75W of power from the PCI-E slot to maintain backwards compatibility with the older 1.1 standard. This means the card requires an additional six-pin power connector, which like the old GTS is situated on the back edge. Together these provide enough power to satisfy the card's 140W TDP.