Negative consequences of an overpowered PSU

[Shades1484]

Lets say your building a rig, basic at first, but planning on upgrading and swapping out better parts as they become affordable.

The power draw at first is about 1000va / 599w

When upgrades will be finished down the line (lets say a year from now) the power calculation is about 2000va / 1197w

Does it make sense to get a PSU that will supply the final product? (1197w / 2000 volts)

Or will it cause damage (or a fire) having a 1197w PSU for a 599 power draw?

[AresKrieger]

Slight inefficiency, and they cost more that's all.

 

So no it won't kill your rig @Shades1484

[Curufinwe_wins]

Lets say your building a rig, basic at first, but planning on upgrading and swapping out better parts as they become affordable.

The power draw at first is about 1000va / 599w

When upgrades will be finished down the line (lets say a year from now) the power calculation is about 2000va / 1197w

Does it make sense to get a PSU that will supply the final product? (1197w / 2000 volts)

Or will it cause damage (or a fire) having a 1197w PSU for a 599 power draw?

PSU efficiency decreases with decreased load, but it is perfectly safe. Overpowering a PSU however is not safe, and many times will just lead to a system shutdown.

[thekeemo]

wasted $$

[vanished]

2000 volts will absolutely kill anything you plug in

 

But there are only 2 real downsides to an excessively powerful PSU: Higher upfront cost, and lower efficiency when running.  It's not going to damage anything though.

[GzeroD]

Getting a bigger one now will save you the cost of buying 2 PSUs which is a lot more than the electricity will cost.

 

also using a higher power psu may lower the psu fan noise/load considerably while your using the lower power configuration depending on PSU

 

 

IMO unless you want a backup PSU later just get the big one now.

[DannyRyu]

wasted $$

actually saved $$ because you don't have to buy a 2nd PSU later on

[GzeroD]

2000 volts will absolutely kill anything you plug in

 

 

I'm going to assume he meant to put 2000VA (volt/amps)

[vanished]

I'm going to assume he meant to put 2000VA (volt/amps)

yeah I think so but he literally typed out "volts".  It's like the written "one" in !!!1!11!!11!!one!!!!

[OddsCrazyStuff]

You are not getting less efficiency with less load, its the other way around: https://en.wikipedia.org/wiki/80_Plus

Power supply's are most efficient at 50% load.

[GzeroD]

You are not getting less efficiency with less load, its the other way around: https://en.wikipedia.org/wiki/80_Plus

Power supply's are most efficient at 50% load.

and it is at it's lease efficient sub 20% load. if you PC idles a lot (like most do) and your pc uses say only 10-15 of your PSU's capacity its is using the energy less efficiently per watt than if it where pulling more.

here is an image of a pretty common efficiency curve for a higher end 900w PSU

[Mr.McMister]

You are not getting less efficiency with less load, its the other way around: https://en.wikipedia.org/wiki/80_Plus

Power supply's are most efficient at 50% load.

Depending on the PSU design the percentage load for peak efficiency changes. Efficiency increases as it approaches this level of usage whether up or down. So with a heavily overpowered psu at say double the capacity of the the peak system load will be most efficient at peak load, but less so when the system is under light or idle load like it is most of the time.

[vanished]

You are not getting less efficiency with less load, its the other way around: https://en.wikipedia.org/wiki/80_Plus

Power supply's are most efficient at 50% load.

Well, maybe I should have been more clear.  If your power supply can provide twice* (or more) as much power as you need, increasing it further will make it less efficient, but if your power supply is supplying only 10%* more than you need, getting a larger one will make it more efficient.

 

* I'm basing these numbers on the fact that in general most power supplies are at peak efficiency around 50% load.  This will vary of course but it is pretty common I think.