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Is high powered PSU bad for motherboard?

Last response: in Motherboards
July 9, 2012 1:44:33 PM


With the plan of expanding later, I am using 850W PSU for z68DB intel motherboard. I have GTX-590 card (which says minimum 750W PSU is recommended).

But I am wondering, if using this 850W PSU is bad for the motherboard (since there seems to be 100w extra power in the PSU).

Would the PSU always output 850W or only as much pulled by the connected components?

The reason I am asking is, an application recently crashed my machine and while attempting the reboot, the motheboard burnt. Wondering if the high-powered PSU is the cause.

Thank you.

Best solution

July 9, 2012 1:55:39 PM

High powered SMPS NEVER burns any motherboard.
That's why it's called A switched-mode power supply (switching-mode power supply, SMPS). It never provides the full power always to the components. Rather it supplies only the amount of power which is required by each component.
July 9, 2012 1:56:48 PM

Short answer no its not bad for the motherboard. The PSU only outputs as much power as is drawn by your components.
Related resources
a b V Motherboard
July 9, 2012 2:00:22 PM

Short answer is no as others have stated. You normally don't want to have your power supply running at 90+% if you are going to have it running 24/7. They get loud and hot which can cause them to burn out quicker. Normally I like to keep mine in the 40-80% load range depending on funds and duty cycle. It is pretty easy to plan accordingly.
July 9, 2012 2:03:05 PM

Ah..ok. Thank you for the confirmations. Its helpful. My burnt reason then must be something else. May be too heated up system or missing ground something like that, I think.
Wish they can provide 'fuse' or some similar on the motheboards.
July 9, 2012 2:03:40 PM

Best answer selected by KrishnaPG.
July 9, 2012 2:05:22 PM

Glad to be of service. :) 
Who was the manufacturer of the 850W SMPS?
a c 715 V Motherboard
a b å Intel
July 9, 2012 2:12:17 PM

^+1 You could have a 1500W+ PSU and the output is equal to the wattage drawn my the 'PC' and its components.

Ideally, its better to have a slightly oversized than undersized PSU. Further, to avoid unnecessary replacement plan ahead if considering multiple GPU's and or other future added components. Most PSU's are most efficient and most importantly 'Quite' @ 40%~60% load. I generally recommend a Bronze or higher rating, Japanese capacitors, and a PSU with voltage protection and in particular Active Power Factor Correction (PFC).

Great resource for sizing -> the default are fine for most folks and don't forget to add 30% Capacitor Aging factor. PSU's lose up to 20%+ capacity due to 'electrolytic capacitor aging.'