What wattage Power Supply?

[Carsonwrobel]

Parts List
Intel i7 4790k
8GB G Skill 1600 RAM
EVGA GTX 970 4GB
Gigabyte Z97 Gaming 3 Motherboard
1 Crucial MX100 256GB SSD
1TB HDD
All in a Corsair Spec 03 Case

 

[lehtv]

500-550w, though a bigger unit doesn't hurt if it's not more expensive. Newegg has Antec HCG-620M for $40 AR: http://www.newegg.com/Product/Produc...82E16817371059

 

[lehtv]

I would say a minimum 600W power is needed for your PC specs. Go for Corsair VS650 or Antec VP650P.

A good 650w unit can power two 970s. A single 970 only uses about 180w

 

[meeshu]

With no overclocking, no extra fans, no liquid cooling, and nothing else extra, system power requirement would be about 300W. To allow for extras, and/or for some overclocking and for PSU degradation due to aging, suggest a good quality PSU rated at a minimum of 500W.

 

[Carsonwrobel]

Ill probably get a hyper 212 cooler for my cpu and 2-3 more case fans. I think I'm going to go with 650

 

[lehtv]

Fans use about 5 watts each, at most.

 

[jeffnc]

The thing to keep in mind is that the power is split up among the output voltage lines. When you buy a 750W PSU over a 500W PSU, you don't just automatically get 250W more to use any way the PC sees fit. It's available as more current to the various 12, 5 and 3.5V lines, but split up. It's not all available for your video card, for example.

 

[TemjinGold]

There's zero need to keep that in mind. The OP does not need more than a 500-550 unit.

 

[Spungo]

A quick google search gets results of people saying a 970 needs 28A on the 12V rail minimum. It wouldn't hurt to overshoot by a bit. Look for 40A or better on the 12V.
The PSU in the second post says it supports 48A, so that should be good enough.

I'm inclined to think one should go way over the top when it comes a gaming power supply. If you get a really good one, you can keep it for half a decade and use it in multiple computers.
Power supplies also seem very sketchy. I think they guess the values for half of these numbers. Speakers and amplifiers are like that too. 1000W sound!*
*we're just guessing

 

[jeffnc]

There's zero need to keep that in mind. The OP does not need more than a 500-550 unit.

Which was my point, so thanks for repeating it

 

[jeffnc]

Power supplies also seem very sketchy. I think they guess the values for half of these numbers. Speakers and amplifiers are like that too. 1000W sound!*
*we're just guessing

It's true - there are lots of ways to fudge the specs to put whatever you want on the box when it comes to things like "watts".

It was not long after CDs came out that I started seeing speakers labeled "Digital Ready" or "Digital Compatible". That was pretty funny.

I think the best thing to do is read the reviews about the recommended power supplies (since the best reviews include broad and independent testing), and then get more than you think you'll need so the PSU isn't taxed.

 

[lehtv]

The thing to keep in mind is that the power is split up among the output voltage lines. When you buy a 750W PSU over a 500W PSU, you don't just automatically get 250W more to use any way the PC sees fit. It's available as more current to the various 12, 5 and 3.5V lines, but split up. It's not all available for your video card, for example.

Actually, that's incorrect. Since almost all of the power used by a modern computer is +12V power, a 750w unit will typically have around 250w more on the +12V compared to an equivalent quality 500w unit.

 

[jeffnc]

Just because most of the power used is 12V doesn't make my post incorrect - it's still completely correct. And the extent to which it matters depends a lot on the design of the PSU.

For example, here are some specs on 2 Corsair PSUs:
CS450: the 12V section has a max load rating of 35.5A, and 426W.
CS650: the 12V section has a max load rating of 51A, and 612W.

So yes, most of that power - 186W - goes to 12V. But not all.

Ultra:
LSP 450: 24A, 288W
LSP 650: 38A, 456W

So now it's only 168W difference.

Huntkey:
ATX160: 7A, 84W
ATX350: 10A, 120W

Now there's only a 36W increase in power for the 12V line between 2 power supplies with a 190W difference in power rating.

So the specs matter, but always, not all the power will be available where you want it if you're just thinking of one component.

And if you happen to be looking at adding components that take 5V or 3.3V power, then you're going to be even further off in your calculations if you're trying to beef up your power supply to support them.

 

[lehtv]

Just because most of the power used is 12V doesn't make my post incorrect - it's still completely correct. And the extent to which it matters depends a lot on the design of the PSU.

For example, here are some specs on 2 Corsair PSUs:
CS450: the 12V section has a max load rating of 35.5A, and 426W.
CS650: the 12V section has a max load rating of 51A, and 612W.

So yes, most of that power - 186W - goes to 12V. But not all.

Yeah... and CS750 = 744W on the +12V. A 100W increase rated wattage increases +12V rating by 132W! Whoops!

Ultra:
LSP 450: 24A, 288W
LSP 650: 38A, 456W

So now it's only 168W difference.

Huntkey:
ATX160: 7A, 84W
ATX350: 10A, 120W

Now there's only a 36W increase in power for the 12V line between 2 power supplies with a 190W difference in power rating.

What made you pick these units in particular? Huntkey, Ultra...? Who buys these?

Huntkey and Ultra aren't exactly brands which are known for producing units whose rating is representative of what the units are actually capable of outputting. In fact, I'd be inclined to put them in the opposite category of brands whose units you should never attempt to run at full wattage in the first place. And if the rated wattage shouldn't be taken seriously, then neither should the +12V rating. Instead, you should look at units which are known to perform well at their rated wattage.

So the specs matter, but always, not all the power will be available where you want it if you're just thinking of one component.

And if you happen to be looking at adding components that take 5V or 3.3V power, then you're going to be even further off in your calculations if you're trying to beef up your power supply to support them.

So, if we look at the carefully picked Corsair CS450 vs CS650 comparison, explain to me how it is "the thing to keep in mind" that 14W out of the 200W increase in rating is not on the +12V? How exactly is this useful information?

 

[jeffnc]

What made you pick these units in particular? Huntkey, Ultra...? Who buys these?

Relatively few buy Ultra and Corsair, while Huntkey in its rebranded forms is very common. They're a top supplier and one of the most plentiful if not most plentiful coming out of China.

The point being - you should keep in mind how power supplies are spec'ed and designed. Don't assume that just because you add 200W to a power supply that you're going to get 200W where you want it. It was true when I first wrote it and it's still true now. You should shop and read reviews and keep in mind how the power supply is designed and what quality the power supply is and how that company measures things.

And to be more specific about the last sentence in your previous post, a 750W power supply will never have 250 more watts available on the 12V line than a 500W power supply. The only question is how much less.....

So, if we look at the carefully picked Corsair CS450 vs CS650 comparison, explain to me how it is "the thing to keep in mind" that 14W out of the 200W increase in rating is not on the +12V? How exactly is this useful information?

First of all, you said my information was incorrect, and I was correcting you. What I said was true, regardless of the fact that some power supplies don't drop much on the 12V line. Second, that was one example, while I showed others that are different from that. So keep in mind that you're not getting all the extra power where you want it, and the amount can very from "most" to "surprisingly little".

 

[lehtv]

Relatively few buy Ultra and Corsair, while Huntkey in its rebranded forms is very common. They're a top supplier and one of the most plentiful if not most plentiful coming out of China.

Relatively few buy Corsair? What?

I probably should've worded my post differently. By "who buys these?" I meant that Huntkey and Ultra are not popular among users who want a quality unit. Corsair, on the other hand, is.

The point being - you should keep in mind how power supplies are spec'ed and designed. Don't assume that just because you add 200W to a power supply that you're going to get 200W where you want it. It was true when I first wrote it and it's still true now. You should shop and read reviews and keep in mind how the power supply is designed and what quality the power supply is and how that company measures things.

Funny how you assume I don't read PSU reviews.

The mere fact that +12V is almost all of the power a modern PC uses makes your whole point irrelevant. No one goes around looking for a more powerful unit so they could power hundreds of watts worth of +5V or +3.3V hardware.

The only real world consideration is "does this unit have enough on the +12V for my purposes". This consideration is also the only one relevant to this thread - we're talking about a gaming PC. The only thing that's going to potentially make the OP want a higher wattage unit is so that it could power a more power hungry CPU or GPU setup, both of which rely purely on the +12V rail.

If you're buying a quality unit, with a few exceptions, its rated wattage will be roughly representative of peak +12V wattage. Thus, contrary to what you're saying, distribution of power between rails is not "the thing to keep in mind".

And to be more specific about the last sentence in your previous post, a 750W power supply will never have 250 more watts available on the 12V line than a 500W power supply. The only question is how much less.....

You're talking about being "more specific" yet you ignore that fact that I specifically said "around 250w more", not "exactly 250w more". Despite that, I'll prove you wrong:

http://www.realhardtechx.com/index_archivos/Page447.htm
Corsair CX500M = 456W on the +12V
Corsair CX750M = 744W on the +12V -> almost 300W more

http://www.realhardtechx.com/index_archivos/Page1418.htm
Silencer MK III series, same thing as above, but different OEM
Silencer MK II series, difference over 300W between 500W and 750W units, made by Sirtec

http://www.realhardtechx.com/index_archivos/Page673.htm
Antec EA-500D Green = 444W on the +12V
Antec EA-750D Green = 750W on the +12V, again over 300W difference

First of all, you said my information was incorrect, and I was correcting you. What I said was true, regardless of the fact that some power supplies don't drop much on the 12V line.

I said it is incorrect to think that you need to keep power distribution between rails in mind when considering a higher wattage unit. It is a non-issue, as explained above.

 

[MongGrel]

500-550w, though a bigger unit doesn't hurt if it's not more expensive. Newegg has Antec HCG-620M for $40 AR: http://www.newegg.com/Product/Produc...82E16817371059

This.

Unless you're adding another GPU etc will be fine, I have an Antec CP-850 myself honestly that I have been using years now to go with this 1200 case I bought very cheap at the time for multiple GPU's, but it's overkill with one card in it now.

When you buy way over what you need you just drag your efficiency down I believe.

Corsairs are probably one of the most popular PSU's from many forums I read, though I'm an Antec Fanboi myself.

 

[jeffnc]

The mere fact that +12V is almost all of the power a modern PC uses makes your whole point irrelevant. No one goes around looking for a more powerful unit so they could power hundreds of watts worth of +5V or +3.3V hardware.

Just because this is an enthusiast forum doesn't change the general facts, and doesn't make what I said wrong. The vast majority of power supplies in the world are not that great. Lots of people reading this forum have bought pre-built computers, with no idea of what's in the power supply other than what the general specs said, if they even read that.

If you're buying a quality unit, with a few exceptions, its rated wattage will be roughly representative of peak +12V wattage. Thus, contrary to what you're saying, distribution of power between rails is not "the thing to keep in mind".

Notice how you added in a big IF there that I didn't say - IF you're buying a quality unit, and part of the definition of "quality unit" is that is splits up the output among the voltage rails intelligently.

Look again at a Huntkey PS. The previous comparison was a little confusing because they change the style of some models, but:
160: 3.3V - 7A, 5V - 8A, 12V - 7A
250: 3.3V - 20A, 5V - 21A, 12V - 17A

Would you design a power supply where there's less current available on the 12V line? And where as you increased the power, you dropped the ratio even less? Now when you add up those totals, it doesn't add up to the designated wattage so it's hard to know what they're trying to do (but this part is true with most power supplies, even good ones.)

Corsair CX500M = 456W on the +12V
Corsair CX750M = 744W on the +12V -> almost 300W more

Let's just think about those specs for a minute. You've got a power supply supposedly giving 250 more watts than the other, and yet somehow it's providing 288 more watts just on the 12V line alone. You realize that doesn't add up, right? It's very difficult to compare apples to apples in these - I admit with my examples as well.

 

[TemjinGold]

jeffnc: Your concerns were true like 20 years ago when people were on AT PSUs. Today, no one cares how the power is split. You will never find anyone who needs to buy a bigger PSU because they are lacking in the 5V or 3.3V department unless they bought trash like Huntkey. Especially for the OP. You are needlessly overcomplicating things with concerns that are obsolete.

Update: I want you to look carefully at the OP's post. Take a deep breath first. Notice, the OP has those parts and wants advice on what size PSU to buy. The OP is not going to accidentally end up with junk like Huntkey without knowing it. Why do you persist with your nonsense on this split stuff? You said it yourself, this is an enthusiast forum. Therefore, anyone coming here to ask for advice on a PSU they HAVEN'T BOUGHT YET is not going to need what you posted.

And yes, you are wrong as the other guy proved to you. Accept it and let it go.

 

[jeffnc]

When you buy way over what you need you just drag your efficiency down I believe.

Well, usually that's true. Most power supplies operate less efficiently when they're way down in their power range. But I think that's more a question of how much power you want to burn. i.e. a big power supply might cost you more on your electric bill than one operating more within its expected range. So you don't want a 1000W unit for a computer drawing 150W most of the time. But still, I'd rather have headroom than cut it real close.

 

[MongGrel]

jeffnc: Your concerns were true like 20 years ago when people were on AT PSUs. Today, no one cares how the power is split. You will never find anyone who needs to buy a bigger PSU because they are lacking in the 5V or 3.3V department unless they bought trash like Huntkey. Especially for the OP. You are needlessly overcomplicating things with concerns that are obsolete.

Update: I want you to look carefully at the OP's post. Take a deep breath first. Notice, the OP has those parts and wants advice on what size PSU to buy. The OP is not going to accidentally end up with junk like Huntkey without knowing it. Why do you persist with your nonsense on this split stuff? You said it yourself, this is an enthusiast forum. Therefore, anyone coming here to ask for advice on a PSU they HAVEN'T BOUGHT YET is not going to need what you posted.

And yes, you are wrong as the other guy proved to you. Accept it and let it go.

+1

 

[jeffnc]

jeffnc: Your concerns were true like 20 years ago when people were on AT PSUs. Today, no one cares how the power is split. You will never find anyone who needs to buy a bigger PSU because they are lacking in the 5V or 3.3V department unless they bought trash like Huntkey. Especially for the OP. You are needlessly overcomplicating things with concerns that are obsolete.

No one cares, assuming it's done correctly. Otherwise you're not getting what you paid for.

And no - no one would want a bigger PSU because they're lacking in the 3.3 or 5V dept, and yet that's where Huntkey puts their power, which is the point. That and lots of people buy computers with Huntkey PSs in them. And even if people aren't buying Huntkey PSs separately, they're still buying Ultra, and god knows what else in OEM form from wherever. They might replace their old 350W PS that died with a new 400W PS that has even less 12V power.

I mean, yeah, you could just say "buy a quality PS" and be done with it and claim anything more is overcomplication. But that's hardly the m.o. of this forum, is it? I'm just stating one of the attributes of a quality PS.

OK, instead of "the thing to keep in mind" I should have said "one of the things to look for in a quality PS."

 

[MongGrel]

You are kind of arguing against yourself now.

Is pretty much a moot point.

 

[jeffnc]

Update: I want you to look carefully at the OP's post.

Actually I was replying to akshatv - apparently my browser hadn't updated with posts in between.

And yes, you are wrong as the other guy proved to you. Accept it and let it go.

Well, you seem as much or more interested in being right than me, so I suppose I could say the same to you.

But since you brought it up, no he didn't prove me wrong. Check the math and compare apples to apples.

CX500: 3.3v - 25a, 5v - 20a, 12v - 38a
add that up and you get 638.5W, not 500

CX750: 3.3v - 25a, 5v - 25a, 12v - 62a
add that up and you get 951.5 W, not 750

So that is an increase of about 315W, not 250W. And the increase in 12V wattage is only about 290, less than 315. So comparing apples to apples isn't easy.

 

[MongGrel]

He was just more interested in passing along valid information.

I'm outa here