For all of our testing, power-saving features were disabled and Windows 7’s power options set to High Performance. Keeping this in mind, let’s take a look at the total system power usage measured from the AC source.
Loading the system's processor and graphics card with FurMark and Prime95 gives us a good look at the maximum potential power draw the system could face.
Looking back, the June PC barely used more than 250 W, and even stayed below 300 W once we overclocked it. Factoring in roughly 80% efficiency meant the peak draw from the PSU was around 235 W. Turning to the current $400 build, peak consumption under full load is 237 W input, or roughly 190 W draw from the power supply.
Notice that the over-volted stock CPU results in higher power consumption at idle and full GPU load. By reducing the CPU voltage in the BIOS, we were able to unlock a fourth processing core and do a little overclocking, in the end barely realizing any increase in consumption when loading all cores in Prime95.
Increased voltage not only results in higher power use, but it also generates more heat. Dialing back the CPU voltage was a key factor in being able to unlock this processor’s dormant core and still run stably with the stock cooler. Of course, we certainly could have also under-volted the stock-clocked system, thus reducing the temperatures at AMD's default frequency.
- How Low Can You Go?
- CPU and Cooler
- Motherboard And Memory
- Graphics Cards And Hard Drive
- Case, Power Supply, And Optical Drive
- Test System Configuration And Benchmarks
- Benchmark Results: Synthetics
- Benchmark Results: Audio/Video
- Benchmark Results: Productivity
- Benchmark Results: Call Of Duty: Modern Warfare 2 And Crysis
- Benchmark Results: DiRT 2 And S.T.A.L.K.E.R.: Call Of Pripyat
- Maximizing Graphics Potential
- Power Consumption And Temperatures
- Performance Summary And Efficiency