How many watts should a PSU for a PC build have?

ineedguidance

Commendable
Apr 5, 2016
7
0
1,510
Hello. I need help with wattage count for a power supply.

Is there a general rule that people should follow when trying to pick a PSU for a build? For example, a friend told me that your power supply's wattage should be a little less than twice as many watts your build uses. He says to follow that rule because people should "just be safe."

My build currently uses 355 watts. What should my PSU wattage be?

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The build on PC Part Picker: http://pcpartpicker.com/p/zbK6nQ

In addition, what should it be if I were to replace the GTX 970 with a GTX 1070?
 
Solution
PCPartPicker part list / Price breakdown by merchant

Power Supply: SeaSonic G 550W 80+ Gold Certified Semi-Modular ATX Power Supply ($68.99 @ NCIX US)
Total: $68.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-05-23 20:59 EDT-0400

or

PCPartPicker part list / Price breakdown by merchant

Power Supply: EVGA SuperNOVA GS 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($70.98 @ Newegg)
Total: $70.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-05-23 21:00 EDT-0400

Dark Lord of Tech

Retired Moderator
PCPartPicker part list / Price breakdown by merchant

Power Supply: SeaSonic G 550W 80+ Gold Certified Semi-Modular ATX Power Supply ($68.99 @ NCIX US)
Total: $68.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-05-23 20:59 EDT-0400

or

PCPartPicker part list / Price breakdown by merchant

Power Supply: EVGA SuperNOVA GS 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($70.98 @ Newegg)
Total: $70.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-05-23 21:00 EDT-0400
 
Solution
what your looking for on a gaming pc or one that going to be on 24/7 is the wattage on the 12v plus rail. that rail has the gpu and cpu on it. look online at other power supply load tests. when they put 70-80 percent load on the 12v rail you see that most power supply start running hot. newer units read the temp the power caps are. some are using 40-45c caps now. most of the good units use 50c and higher caps for longer life. most people with gaming pc and gaming gpu push there 12v rail to the max output...it cause the unit to ripple or over heat and lock up. that why going 100w more then needed keeps the power supply 12v rail from maxing out.