What actually does a PSU do?

ZakiiRX

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Aug 24, 2014
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Clearly a newbie xD! So I'm looking at a Corsair CX600 600w... Now, what I was wondering was that my GPU, itself, on there website, is recommended of a System PSU of 600w... Does that mean it takes up the whole PSU and can possibly, EXPLODE?! I also looked at a website a couple of weeks ago by an amazing forumer... My GPU (Gigabyte R9 280x) will only take up roughly 300w... And that's when gaming, which is what I will most likely be doing... Especially games like Battlefiesl, Far Cry, Titanfall etc. I'm sorry if this will hurt you "Experts" and might be a very stupid question to ask but, I'm just wondering... So keep all "Negative comments" to yourself... Plis?
 
It's not likely that a recommended PSU would explode. That said, more capacity is better.

Besides converting AC electricity to DC the PSU smooths and distributes the power to the various connectors. When a PC starts up all of its components are pulling maximum power because it takes more to start a device than it does to keep it running. That's especially true of mechanical devices like HDD's, fans, etc

Calculating power requirements is a matter of summing all the devices' startup power requirements and adding some "head room". For example you wouldn't want a 600W PSU for a system that draws 600W after startup because the system will draw more than that on startup. Head room allows for startup and also fluctuations while running.

As an example think of a car that's maximum speed is 70MPH. It's fine around town but you wouldn't want to drive it 400 miles on an interstate. If the car is capable of 120MPH and you drive it 70MPH, no big deal. That 50 MPH is the head room.

By the same token, you don't want to be running a 600W PSU at 550W all day long. It will work but the PSU won't last as long. Twenty percent is the usually advised amount of head room. One would think the PSU site would have calculated that into the recommendation. On the other hand, they are in the business of selling PSU's.
 

nanzer

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Jul 12, 2011
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By the way, don't listen to Tim Greven. If 600W is recommended, then that includes what the rest of the PC may use. Unless you have a couple of GTX Titans, there's no way you'll hit 600W power usage with just your GPU.