Calculating Power Requirements for the Computer

Having ordered the main component for the computer through Amazon (USA) and also through PC Online (NZ) I've looked at a couple of websites to see what kind of power supply unit (PSU) I will need. I went to the Cool Master site (http://www.coolermaster.outervision.com/) and also Power Supply Calculator (http://powersupplycalculator.net/).  A search on Google reveals that there are also many others that you could choose from.  However, the information below show the results from the Power Supply Calculator site.  Interestingly and reassuringly, the results from both sites confirmed pretty much the same power needs.

Idle power: 94 W

Idle power is the power drawn by the system when booted to a desktop while the computer is doing nothing at the given moment. Please note that idle power may be lower when computer screen is turned off or system is in deep sleep. Also if you have disabled any power saving features of the system, the result may vary. Idle power does not include power losses from the PSU itself.

Load power: 390 W

Load power is the average power drawn by the system when running an intense 3D-game with all CPU-cores, drives and peripherals operating at maximum load. Load power is the maximum power the system may use in a typical real-world scenario. Please note that load power is not the absolute maximum power of the system. By running a synthetic benchmark, power consumption may increase even further. Load power does not include power losses from the PSU itself.

Distribution of power

SYSTEM

CPU

GPU

RAM

DRIVES

PERIPHERALS

COOLING

idle

load

Recommended power supply: 490 W

This is the minimum recommended PSU wattage for the selected components. Choosing a lower wattage PSU increases the risk of system to become unstable and noise from PSU to become annoying. Choosing a higher wattage PSU decreases efficiency at lighter loads, but leaves a margin for overclocking and future upgrades and also ensures the PSU stays cool and quiet.