The Forgotten Vital Hardware Component

Last Updated: 30 November 2016

The PSU – Power Supply Unit

Pic of Power supply unit
A Corsair 1000W Modular-cabled PSU

One of the most neglected items in the computer workstation is the Power Supply Unit – the PSU. Its purpose is to provide a constant source of stabilized power over a wide range of loads. There must be enough reserve power available that in the event of a sudden current draw, the voltage does not drop appreciably. Stability must be maintained in a number of simultaneous circuits at different voltages (primarily +5V and +12V).

No matter what the advertising wizards would have you believe, the laws of physics are implacable: If a chip is suddenly commanded to calculate intensively, it will draw more current and generate more heat. The CPU, the motherboard chipset and the graphics processor are the worst culprits. There has to be enough power available from the PSU to quench this voracious electronic thirst.

Guess what? most PSU’s are just not up to the task. An under-powered PC will appear to run fine…

  • but in the best case, the PSU will often be running at maximum design limits (which any engineer will tell you is not a good thing), and
  • in a severe case the PC will temporarily suspend it’s calculations for a few milli-seconds (effectively throttling down) while it waits for the voltage to rise again, or
  • in the worst case, the machine will act erratically and often just reboot, freeze or even corrupt your data.

Calculating the real wattage needed for trouble-free operation depends on exactly what components are in the computer and the typical operations that the software is carrying out.

Did you know that most computer workstations just run at “idle” for over 98% of the time they are switched on? The problem arises in that 2% period when the machine is expected to perform that there just isn’t enough power available and the supply voltage to the components drops.

A high-end simulator PC  will typically requires a PSU of between 500W and 1200W depending on the Graphics card that is fitted. A good rule of thumb for calculating the power required by a modern flight simulator PC is to look up the manufacturer’s power requirement for the graphics card (Google is your friend) and double it.  Don’t buy the cheapest – carefully look at test reports.