Power consumption
We measured system power consumption, sans monitor and speakers, at the wall outlet using a Watts Up power meter. Power consumption was measured at idle and under a load consisting of a multi-threaded Cinebench 2003 render running in parallel with the "rthdribl" high dynamic range lighting demo.

Our system power consumption tests don't completely isolate the chipset, but it's interesting to see the 680i SLI motherboard consuming more power than one based on the 590 SLI at idle, but not under load. Intel's P965 and 975X chipsets are the real low-power champs here, though.

Overclocking
Nvidia is quick to push the nForce 680i SLI's overclocking potential, so we spent a considerable amount of time abusing the chipset's front-side bus. After lowering the CPU multiplier to take it out of the equation, we were able to hit a maximum stable front-side bus speed of 360MHz. Above that speed, the board refused to post, even with higher front-side bus and north bridge voltages. We even tried front-side bus speeds between 360 and 560MHz in 20MHz increments to see if skipping to higher speeds would work, to no avail.

Frustrated, we wondered if the engineering sample Core 2 Duo E6700 we were using for testing could be the culprit, so we picked up a retail E6300. That chip did the trick, and we were soon running our board with a blistering 445MHz front-side bus.

At that speed, our E6300 was clocked at 3.1GHz, and wasn't even asking for extra voltage. Further attempts to push the front-side bus higher were unsuccessful, though, even after lowering the CPU's multiplier.

Despite the fact that a 445MHz front-side bus is pretty exceptional for a Core 2 Duo motherboard, Nvidia suggested that higher speeds were possible, and sent us a second board for testing.

With our second 680i board, we were able to push the front-side bus all the way up to 490MHz. It was perfectly stable at that speed cranking Prime95 and the rthdribl HDR lighting demo, too. 495MHz would post, but fail to load Windows, while 500MHz wouldn't post at all.

Not content to limit our overclocking escapades to the front-side bus, we turned our attention to the memory. Nvidia shipped the board with a pair of Corsair Dominator CM2X1024-9136C5D DIMMs rated for 5-5-5-15 timings at 1142MHz on the nForce 680i SLI, and we were able to push them to 1200MHz on the board.

Unfortunately, the latest version of CPU-Z doesn't recognize the 680i SLI's memory controller, so we had to resort to nTune to showcase our memory overclock. Look for more extensive coverage of these and other Dominator modules soon.

As is always the case with overclocking, your mileage may vary.