For a good few years now, graphics cards have been the component that draws most power in high end machines. Indeed they can consume up to 300 watts, while a processor that hasn’t been overclocked generally falls somewhere between 50 and 100 watts, with the same for the rest of the configuration (motherboard, hard drives and so on). When you associate several cards in an SLI or CrossFire X, it’s no surprise to see that your graphics solution uses between 50% and 75% of the total power of your system. So what do the various models consume?
Measuring the energy consumption of a graphics cardLast February, we introduced a new protocol that allows us to measure the energy consumption of the graphics card in isolation to the rest of the system. Measuring this value is quite complex because a graphics card draws power from two separate sources:
-The PCI-Express x16 port, which can supply up to 75W
- Additional PCI-Express connectors, each of which can supply 75W (6-pin) or 150W (8-pin)
Measuring the consumption drawn via the additional PCI-Express power connectors is relatively simple because voltage can be taken directly at the graphics card PCB and amperage with a clip-on ammeter. It’s more complex for the PCI-Express port, but doable, and we have been able to set up a system that allows us to take the energy consumption drawn by the graphics card from this source, whether from the 3.3V (generally negligeable and just a few watts) or the 12V.
Last February, we published the readings obtained across 79 cards in four different situations:
- In 2D, with the Windows desktop
- During the playback of Blu-ray H.264 (Power DVD + Chapter 3 of I-Robot)
- In the 3DMark06 Pixel Shader test at 1920*1200
- In the FurMark Stability Test in Xtreme mode at 1920*1200
We use two 3D load tests because, depending on the various architectures, the cards were scored differently in comparison to each other in the two tests. We have now stopped taking the Blu-ray reading as it wasn’t giving us much useful data in comparison to the 2D test. This year, otherwise continuing with the same protocol, we are able to present the results obtained across no less than 93 cards!