Can You Have Too Much Power?

[azreal64]

So I'm building a new computer, and I'm trying to decide on a PSU. At the moment I'm looking at getting an 850W power supply. I'll be running a GTX 680, with two combo drives, an SSD, and an HDD. However, I'm thinking about the possibility of getting a 1000W PSU, with the hope of buying another graphics card for SLI at some point in the future. I'm wondering though if you can damage key computer components by getting a PSU with too much power.

[[R-CON]Psyrus]

You can't damage a computer by getting a high quality PSU with "too much" power. It'll draw/send/whatever how much power each component requires at any given time.

A way that you can damage your computer, is by getting a low quality PSU that has inferior components, overloaded rails or a history of blowing up... I'm looking at you, Shaw.

A system with a high end overclocked CPU and SLI GTX680s will draw ~500W.
GeForce GTX 680 SLI review

Using this and taking into account capacitor degradation over the coming years, you'd want around a 33% overhead. 500*1.33 = 665W. Thus, a 650W supply (80+ gold) would be fine. A point to also consider, is that PSUs have an optimally efficient operation (draw %) range. This is usually between the 50% mark but goes somewhat higher. With this in mind, I would say a 750-850W PSU would be ideal in this case... assuming it's a nice, high quality PSU.

Some recommendations in order of price:

• Silverstone Strider Plus 750W
• Antec High Current Gamer 900W
• Seasonic X-850 80Plus Gold 850W
• OCZ Technology ZX Series 1000W

[Q2M100]

I agree with Psyrus. Get a solid PSU above anything else.

Corsair also makes good PSU's (arguably the best).

[[R-DEV]Ninja2dan]

As others have noted, having a PSU with a high max power output isn't going to harm your computer as long as it's a quality unit and you properly follow normal PC maintenance practices and install it correctly.

My personal recommendation is to install the best PSU that you can afford, but only install the max capacity that you plan on eventually using. In other words, don't go installing a 1600W just to be a pimp, knowing that you'll never need it.

With most newer PC "advanced" components such as high-end video cards, uber sound cards, video capture cards, TV tuner cards, lots of RAM, etc they will draw more power than some lame-ass stock Dell or Wal-Mart off-the-shelf special. While those ghetto box units can get away with running a 450W (onboard video/audio etc), you'll want nothing less than a 600W-750W for a basic custom build. If you plan to do any upgrades in the future such as SLI/Crossfire, aim for 850W minimum. If you can afford a good 1000W or 1200W, do it.

Another personal suggestion, go for a modular PSU. I personally use the Ultra series modular, but there are a few other good manufacturers. Modular PSU's will allow you to use only the cables you need right now, but have the option of plugging in additional cables for new components as you upgrade. Not only does this help keep clutter to a minimum and make your internals look pretty, but it boosts internal air flow which therefore increases system cooling capability. Modular systems also let you plug in cables to meet your specific needs, be it MOLEX or SATA or whatever. And if at some point down the road one of your cables or connectors fail, you just replace that single cable and not the whole PSU.

[[R-COM]LITOralis.nMd]

To just answer your question,

Yes, you CAN have a too powerful PSU.
The efficiency of the PSU is not linear, it is usually inefficient if under 20% utilization and inefficient again if over 85% inefficient.
There is an old website called johnnyguru.com which is still the Bible for all PSU information.
Here is the answer to your question:
Power Supply FAQs

And here is the rest of the PSU FAQ:
Power Supply FAQs

That being said, if you plan to build a gaming rig as of right now, to get a PSU that would be so underutilized as to lose its efficiency would cost you upwards of $250 for the PSU alone.

Technically, yes.
In your practical sense, no.

[[R-CON]Psyrus]

Originally Posted by [R-COM]LITOralis.nMd

That being said, if you plan to build a gaming rig as of right now, to get a PSU that would be so underutilized as to lose its efficiency would cost you upwards of $250 for the PSU alone.

Technically, yes.
In your practical sense, no.

Just to be sure, a low efficiency rating at the <20% utilization wouldn't serve to *damage* the components, it'd just be a higher wall draw per output watt, right?

[azreal64]

Thanks guys, I'm thinking about getting a Cooler Master 1000W PSU.

[[R-COM]LITOralis.nMd]

Originally Posted by Psyrus

Just to be sure, a low efficiency rating at the <20% utilization wouldn't serve to *damage* the components, it'd just be a higher wall draw per output watt, right?

Yes, that is usually correct.
Theoretically there could be increased modulation due to the components draw being so low the continuous conditioning of the incoming power is below the resistance level required to provide clean, steady output power. This won't ruin components but over many years can lower lifespans of (cheaper) components.

But that's usually not a consideration until you are dealing with equipment 10 times as expensive as a gaming PC.

TO the original poster, that 1000W PSU range is perfectly fine for your build, and it will probably last you unti your next build some years down the road. Be aware that the capacitors in PSUs degrade over time, dependent on the quality of the capacitors, expect 15% to 30% reduced Wattage output in 3 to 5 years.

Put in perspective, my Corsair TX 750W bought in 2007 for my prior PC, and is in my current gaming PC working just fine.

[[R-CON]Psyrus]

Originally Posted by [R-DEV]Ninja2dan

While those ghetto box units can get away with running a 450W (onboard video/audio etc), you'll want nothing less than a 600W-750W for a basic custom build. If you plan to do any upgrades in the future such as SLI/Crossfire, aim for 850W minimum. If you can afford a good 1000W or 1200W, do it.

Just as an FYI, the above is rather factually incorrect. It's a common misconception but incorrect, nonetheless. See my post above (the first response). I explain the actuality in the latter half of the post.

[Qwertfyu2]

I figured I should bump this one instead of creatinga new thread.

So I'm going to buy a new PC and here's what I'm getting:

Gateway DX4870 UR23P Desktop PC - 3rd gen Intel Core i5-3470 3.2GHz, 8GB DDR3, 1TB HDD, DVDRW, Wi-Fi, Windows 7 Home Premium 64-bit at TigerDirect.com

I plan to upgrade the graphics card to a Radeon HD 6870. The computer above ^ only comes with a 300W PSU.

Do I need to upgrade my PSU? I'm pretty sure I do.

If so, how much Wattage should I upgrade it to?

Thanks!