Scott Mueller's Upgrading and Repairing PCs Forum

Power Supply Units (PSUs) have always been one of the most failure prone components in a PC. This is often due to the fact that the units included with pre-built systems usually emphasize cost over quality and performance. As a guide, here are some of the features I look for in a PSU, which are generally indicative of high quality, high performance units:

• The types and numbers of connectors (24-pin main, 4/8-pin +12V, 6/8-pin PCIe, SATA, etc.)
• Single-rail +12V design
• 80-plus (or better) certification
• SLI and/or Crossfire certification
• Active Power Factor Correction

Other features to consider include fan noise, modular connectors, sleeved wiring, etc.

Brands that I often recommend including these features are PC Power & Cooling and Corsair power supplies. Both of those companies feature single-rail designs which are primarly manufactured by Seasonic. Scott.

Scott, you recommended that we could use the PSU calculator at ASUS or we could use your estimates times 1.5. Which method is more accurate? Should I multiply their answer by 1.5 or do you think that it is already in their formula? Keith

Both are conservative estimates. It does seem that the ASUS calculator errs on the side of caution (i.e. 1.5x+ what is actually required). A couple of things to keep in mind are that having more PSU capacity than necessary is always better than having less, however having an extreme excess in capacity will reduce overall efficiency, thereby wasting some energy and costing more money to run. Scott.

I will rerun the numbers because I got drastically different results when I factored the 1.5 for ASUS' results. Perhaps they already factored in the half to their total at their calculator. On your numbers I used the high end of the range.

I'll let you know the totals of both numbers so that you can advise which results I should use.