Questions about power supply requirements 9 replies

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Supa

People say I post too much

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1st April 2009

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#1 7 years ago

I've been planning to get a few upgrades when the new Ivy Bridge processors come out. I want to know more about power supplies and dependencies though, because I virtually know next to nothing.

I hear two things. Either get a power supply that's more than what you need, or get a power supply that's just what you need. Right now, I'm pretty sure I've got the power I need for this rig, but I kind of want to clear that up. What's better, to have a power supply that's more than what you need or just what you need, and why?




*Daedalus

A Phoenix from the ashes

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18th April 2006

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#2 7 years ago

Ideally you want a PSU you to be able to supply about 120% of what you need. For example, if you had a 600W system, you'd want around a 700W PSU. This is because PSUs are most efficient at around 80% power output. At 5-20% they can be anywhere from 50-75% efficient, 20-50% is a little better, usually 60-80%, then at 50-80% output it's usually about 80-90% efficient, and from 80-110% it drops back to 70% or so efficiency.

eff-comparison.png

This shows what the curve of a good PSU looks like. It's also the reason you don't cheap out on no-name units; you'll get the low end of the numbers I gave, and if you try (don't) to pull 100% the power of what the specs on some of those tell you, they'll explode. :)




Supa

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#3 7 years ago

Indeed, I'll most likely stick with Corsair, unless I end up needing something over 1000w. I'm not sure what they've been doing, but they currently only have 1050w power supplies and 1200w power supplies on Newegg. Highest under that is 850w.




*Daedalus

A Phoenix from the ashes

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#4 7 years ago

You want a 1000W PSU for a 950 and a 560Ti? You know a 550W unit will power that, right? If not a 500W PSU?




Supa

People say I post too much

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#5 7 years ago

No, I was thinking about 1000w for my next upgrade, which will either be an i7-2600k, an SB-E CPU or an IB CPU, and a GTX 580 or 680 (depending on prices, or if I can get a 580 for $400 on Black Friday).

Inb4 "You know the 750w you have right now would be enough for that, right?"

:x




C38368

...burning angel wings to dust

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14th February 2004

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#6 7 years ago

In befores only count if you actually make a separate post.

1000W is massive overkill for that. 750W is probably overkill, as well.




MoreGun89

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27th July 2004

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#7 7 years ago

I'm going for the Corsair Silver if that helps, it's modular, 750W with a gold efficiency rating, despite Corsair being modest and reducing it to silver. Not to mention they have a 10% off code on newegg and the $15 rebate brings it down to a 600W with no price reduction :) Newegg.com - CORSAIR Professional Series HX750 (CMPSU-750HX) 750W ATX12V 2.3 / EPS12V 2.91 SLI Ready CrossFire Ready 80 PLUS SILVER Certified Modular Active PFC Power Supply (ugh, I are good price hunter!) :P

I agree that the 750W is overkill, but good to have if it lasts you the long run in case you want to SLI the 560ti, it may come in handy!


Mother Banhammer



kow_ciller

Gettin' hardware chilly

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16th June 2004

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#8 7 years ago

Kids and your overkill.

I was running a 2600k and gtx560 on a 1200w for awhile.

Things are a bit better with the 2600k and 480, but still just a tad overkill.




>Omen<

Modern Warfare

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1st January 2005

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#9 7 years ago
Supa;5571239No, I was thinking about 1000w for my next upgrade, which will either be an i7-2600k, an SB-E CPU or an IB CPU, and a GTX 580 or 680...

If you're allowing headroom for a possible 580 SLI setup on down the road, that would make sense, but 1000W is definitely more than you need for one 580. Also Nvidia's 600 series, if it's called that, will likely be 28nm, so probably fairly power efficient.




Supa

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#10 7 years ago

Yeah, I was looking at 580 SLI in the future. That's the reason I was going for 580, instead of 680 (or whatever they're going to call it), I could buy one now, and buy another one when the prices drop enough.