NVIDIA nForce 780a SLI Motherboard Round-Up
Hybrid Power, Power Consumption
Before we bring this article to a close, we'd like to cover a few final data points. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the motherboards alone.
According to our results, the new nForce 780a SLI-based motherboards consume considerably less power than the 790FX-based GA-MA790FX-DQ6. Idle power consumption is similar, but under load our 790FX test bed uses much more power. The GA-MA790FX-DQ6 has been known to consume quite a bit of power, and our sample is from a very early batch, which exacerbates the issue. Perhaps other 790FX boards will far better in this comparison, but unfortunately we did not have another available to test in this respect.
We also monitored out test system's power consumption using the Hybrid Power mode available with the nForce 780a SLI when paired with either a GeForce 9800 GTX or GX2 - we used a single GTX. In Hybrid Power mode, the discreet graphics card can be almost totally shut down, which obviously saves power.
As you can see, Hybrid Power mode seemed to work well. The system consumed only seven more watts than it did with no discreet graphics card installed in it at all and 48 fewer watts than it did with the discreet card running in Boost mode.
We should also point out that we noticed the discreet graphics card completely disappeared from Device Manager when Hybrid Power mode was used. Essentially, by shutting down the card, it's like it is no longer installed in the system as far as Windows is concerned.