Is 750w overkill for my PC?

[SafetyPotato]

Hello. Recenty my power supply died and I have been looking for a new one. After some research I thought about getting this one: http://www.amazon.com/EVGA-SuperNOVA-80PLUS-Certified-110-B2-0750-VR/dp/B00KFAFRW6/ref=sr_1_1?s=electronics&ie=UTF8&qid=1428454058&sr=1-1&keywords=EVGA+SuperNOVA+750+B2

At max my PC runs at about 480w and I do plan to do some overclocking in the future, so would 750w be overkill? Do power supplies take as much power from the outlet it needs or does it take a set amount of power from the outlet depending on the capacity of it? Also, I've heard that a PC works less efficiently when you have too big of a power supply. Is this true?

 

[mrmez]

A PSU uses only as much as it needs.

A little hard without knowing your specs, but you could get away with less. However, a good PSU will pay for itself easily in the long run.
I got a top tier 750w about 7 years ago now. Still going strong in my current system.
A 650w would have been fine, but overdoing it means it runs a little cooler, quieter and lasts a little longer.

 

[jovce17]

ITs optimal on around 60-70% usage ....if your system is using 480% optimal PSU with minimal losses on power will be around 650-700W PSU

hte PSU takes a bit more power from outlet then you spend .....each PSU has its wn efficancy ...80+ bronze means that at 80% usage it has 85% + efficancy at 90% usage at least 82% efficancy and at 100% usage at least 80% efficnacy or smthing like that ...you get the point ...so if your system is spending 500 W and it has 80% efficancy then it draws 630W from the power outlet

 

[fudoka711]

That psu will work just fine. In fact, staying around 50-75% load is good to do.

Here's some more info about power supplies that you may find useful: http://www.tomshardware.com/forum/343495-28-power-supply-efficiency-myths

 

[Scibbo]

750W is fine as a future proof if you decide to sli to pc. (Maxewell gtx 960 or 970 gpus)

 

[jovce17]

here is yours PSU
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=393
at 528W usage it has 87% efficancy and it draws 604.2W from outlet

when IDLE its efficnacy will be 76.0W/92.9W >82% .....the only problem with TOO BIG PSu is if the idle system power usage is samler then 10% of the max PSU power....
lets say if you get 1200W PSU ...then for 70 W usage the PSu will have 50% efficancy and it will draw 110W while idle ...thats the overkill

 

[Mr5oh]

If the PSU is 80% efficient, that other 20% will be wasted in the form of heat. So running the PSU at a low load will generally be less efficient, meaning more heat and power wasted.

So let's take the 80 Plus Gold standard, 20% load - 87% efficient, 50% load - 90%, 100% - 87%. Generally the sweet spot is at 50% load. As you can see it's not a huge difference on a quality PSU.

I highly doubt your PC ever draws 480 watts though. Have you measured this value, or is that what a web site calculator told you? I've measured actual power draw on many machines during various benchmarks, and rarely do PCs draw more than 300 watts, many are well under. Also worth noting I'm measuring from the wall, meaning if I measure 300 watts, the PC is actually draw less.

I have found overclocking generally uses about 10%-15% more power (measured). Just for reference my 4690k / GTX 760 build maxes out at 249 watts from the wall during 3DMark11. My media machine G3258 / GTX 750 TI is only 114 watts.

 

[jovce17]

If the PSU is 80% efficient, that other 20% will be wasted in the form of heat. So running the PSU at a low load will generally be less efficient, meaning more heat and power wasted.

So let's take the 80 Plus Gold standard, 20% load - 87% efficient, 50% load - 90%, 100% - 87%. Generally the sweet spot is at 50% load. As you can see it's not a huge difference on a quality PSU.

I highly doubt your PC ever draws 480 watts though. Have you measured this value, or is that what a web site calculator told you? I've measured actual power draw on many machines during various benchmarks, and rarely do PCs draw more than 300 watts, many are well under. Also worth noting I'm measuring from the wall, meaning if I measure 300 watts, the PC is actually draw less.

I have found overclocking generally uses about 10%-15% more power (measured). Just for reference my 4690k / GTX 760 build maxes out at 249 watts from the wall during 3DMark11. My media machine G3258 / GTX 750 TI is only 114 watts.

80W for CPU + 50 W for MOBO HDDs etc+ 150W for 760 that system will spend 280w at PEAK ....it no wonder that it usses only 300W
550W pSU with 40A for 12V will be ideal ....for that PC ....the need for 750 is for amd graphics which spend 250 -300 W alone or for SLI nvidia