Why is everyone OVERDOING Power Supply Wattage?

[halfadder]

Originally posted by: Dopefiend

Originally posted by: halfadder
My school just bought a new server. It's a dual processor rackmount (19 inches wide and 7 inches tall) made by Sun Microsystems and running Solaris (a version of Unix). It has dual 560 watt PSUs!!

... which is about the norm for any half-decent server. Remember, of course, that they're redundant PSUs, so it doesn't actually need 1120W of power.

Ahhh, good point. I should sneak in there and pull one of the plugs to see if it keeps on trucking! 🙂

 

[VirtualLarry]

Originally posted by: Matthias99
Well, of course, they've been doing *that* for years. But it wasn't until fairly recently that a whole plethora of reputable-brand manufacturers started really producing 500-600W PSUs (which can actually put out 500-600W worth of power!) There just wasn't any market for these outside of servers before, and I'm not certain why one has developed all of a sudden.

Oh, good point. I can only assume that it is because of Intel's changing power-supply specs. (ATX12V, EPS, etc., along with the fact that their "Press-hot" CPUs can dissipate 120W), along with the co-inciding production of video cards that need so much power that they have additional on-card molex connectors, and SLI makes this problem doubly-so.

Originally posted by: Matthias99
But if you're not planning on super-high-end SLI or multiple CPUs, 18A should be plenty.

Agreed.

 

[VirtualLarry]

Originally posted by: ribbon13
I have 4 psus in my system (1 pcp&c and 3 meanwell) and I still don't feel like it's enough. That's for 2 cpus, 2 TECs, 8 dimms, a Realizm 800, a X850XTPE, and 16 HDDs. When you got that much cash vested, Overkill (Redundancy for the server-types) is the way to go. Don't forget your UPS!

Those TECs suck up a *lot* of juice, not to mention the spinup power draw of those HDs. Multiple PSUs in that application almost makes sense. I'm curious though, did you take any special pracautions to hook them all up? Did you wire their chassis ground together, and do you have the AC inputs for all of the supplies wired to the same power-strip?

 

[imported_Mitchell]

I got a PC Power & Cooling PS cause I had used them for years, but skimped on my last build of my system. Then I started loosing HD's, one here, one there till I ended up replacing ALL of the drives. So I went adn got another PC Power & Cooling 510 True Watt unit and havent had a HD failure since.

The quality matters not so much the watts. Good quality means better wattage most of the time.

 

[beatle]

Take a look at the duallie in my sig. Its PSU is 5 or 6 years old. It crunches F@H 24x7 on both CPUs and runs backups for my other computers. I bought into the FUD that my Antec 330w was causing crashes in my A64 rig. The OCZ 470 still crashes, so that was a waste.

 

[jonnyGURU]

To reiterate almost everything said here.....

1. A Power supply only delivers what it needs. Get yourself a Kill-A-Watt from Drugstore.com (and a free backpack this month!) If your PC only needs 180W, you're pulling 180W, not 500W.

2. Poor power factor. If your PC only needs 180W, you might need at least 300W to compensate for a 60% power factor. Again, get yourself a Kill-A-Watt and a free bottle of lavender scented window cleaner from Drugstore.com.

3. Overhead. As loads go up (opticals spinning up, heavy HDD use, high CPU or video card use, etc.) your wattage requirements go up.

4. Power delivery across the different rails. You maximum wattage capability if for all of your rails added together. So for example, on one 400W power supply, you might be able to hit the 5V with 20A, like for a VIA based Socket A board that regulates CPU voltage from the 5V rail, but you might not be able to power the same equipment on an nForce Ultra 400 board with the same power supply because that board regulates CPU voltage from the 12V rail and the power supply only has 12A available on the 12V rail.

In other word, you might have a killer, well made 400W power supply, but it doesn't mean squat if you need a bunch of power on the 12V rail and the bulk of the PSU's power is put out on the 5V rail.

That said, you probably DON'T need a 500W power supply. I know that with 60% PF under full load, my PC only actually needs a really good quality 250W, but it's a good piece of mind to have the 500W in there instead. 😉

 

[apoppin]

i think "future-proofing" is the only practical reason one considers an OVERsize PS (unless you consider bragging rights practical). 😉

One year ago, i got a 480w tt for really cheap that'll run a 6800ultra in my system - even though i currently only have a 9800xt in my rig that a budget 350w ran ok . . . . when r520 comes out and the ultras drop in price it is planned to be my last AGP card . . . so that's about 4 years out of a PS for this rig. 😉

Who knows what my next PS will be in a few years? . . . . with multi-core cpus and sli'd GPUs . . . . 600w might be skimpy then so i'll buy when i am am more certain , , , , in the meantime, my 480w TT is stably powering my rig awaiting it's (final) upgrades.

 

[ribbon13]

Those TECs suck up a *lot* of juice, not to mention the spinup power draw of those HDs. Multiple PSUs in that application almost makes sense. I'm curious though, did you take any special pracautions to hook them all up? Did you wire their chassis ground together, and do you have the AC inputs for all of the supplies wired to the same power-strip?

All the IECs are running to an APC SURT10000RMXLT-2TF5 which I picked up at a police auction for $1500. My whole closet acts as a faraday cage. 😀

 

[jonnyGURU]

Man... What's with police auctions. I did an install down in Miami and the IT guy there had about four of those on casters that he bought at a police auction. He got them for only $400 a piece! Guess nobody else there knew what they were!!! 😀

 

[Googer]

Originally posted by: jonnyGURU
To reiterate almost everything said here.....

1. A Power supply only delivers what it needs. Get yourself a Kill-A-Watt from Drugstore.com (and a free backpack this month!) If your PC only needs 180W, you're pulling 180W, not 500W.

2. Poor power factor. If your PC only needs 180W, you might need at least 300W to compensate for a 60% power factor. Again, get yourself a Kill-A-Watt and a free bottle of lavender scented window cleaner from Drugstore.com.

3. Overhead. As loads go up (opticals spinning up, heavy HDD use, high CPU or video card use, etc.) your wattage requirements go up.

4. Power delivery across the different rails. You maximum wattage capability if for all of your rails added together. So for example, on one 400W power supply, you might be able to hit the 5V with 20A, like for a VIA based Socket A board that regulates CPU voltage from the 5V rail, but you might not be able to power the same equipment on an nForce Ultra 400 board with the same power supply because that board regulates CPU voltage from the 12V rail and the power supply only has 12A available on the 12V rail.

In other word, you might have a killer, well made 400W power supply, but it doesn't mean squat if you need a bunch of power on the 12V rail and the bulk of the PSU's power is put out on the 5V rail.

That said, you probably DON'T need a 500W power supply. I know that with 60% PF under full load, my PC only actually needs a really good quality 250W, but it's a good piece of mind to have the 500W in there instead. 😉

You can get one by clicking on the Kill-A-Watt Price List.. They are cheaper at other places than drugstore.com Also I think it is seasonic that also makes one of those too, but the Kill-a-Watt is regarded as the defacto standard.

 

[VirtualLarry]

Originally posted by: ribbon13
All the IECs are running to an APC SURT10000RMXLT-2TF5 which I picked up at a police auction for $1500. My whole closet acts as a faraday cage. 😀

Whoa, 10,000VA..! *drool*
I think that I could power my PC for a week with that after the power goes out!

(Wait, scratch that, the VA rating is for the output capacity of the inverted, the runtime is a factor of battery capacity. Ignore my technically-incorrect stab at humor. 😛 )

 

[jonnyGURU]

Googer: True.. You can get it cheaper elsewhere, but of all of those places that are cheaper than Drugstore.com, I know of one of them and I would never buy from them.

At least I know Drugstore has them in stock, ships on time, has fair shipping ($5 on that item, I think) and really does have a promo every month where you walk away with a bunch of free stuff. I paid $5 more for a forehead thermometer, only paid $4 to ship it and got a free backpack (nice one too!) and a bottle of some sort of spray. A while back, I bought a bunch of aspirin from them and got free shampoo. 😀 Seriously... I have no issue with Drugstore.com if they're going to keep throwing me free stuff, ship on time and are only a few bucks more. 🙂

Seriously though... If you have ANY power questions, the Kill-A-Watt is a freaking AWESOME tool to have. That and a multi-meter and you're set. 😉

 

[bfonnes]

The reason why people go as high as 500+ watts is completely because of overclocking... (edit: especially if they have a toaster! i.e. Prescott). Overclocking your CPU and especially your RAM just sucks power. The other reason is because of some of the crappy supplies that you get actually supply less power than they are rated for... Look in Tom's Hardware article archives for an article on power supplies. They did a test on power supplies, and found a lot that blew up or caused errors, whatever, at much lower wattage than it was rated for.

thg link 1
thg link 2

BFonnes

edit: I am using a sl400 Antec Smartpower in my PC... Barton XP 2500 @ 2100 MHz, Kingston PC2700 RAM, and Rosewill 9600XT @ 560/720, 3 IDE (2 CD, 1 HDD)

 

[jonnyGURU]

Originally posted by: VirtualLarry

Originally posted by: ribbon13
All the IECs are running to an APC SURT10000RMXLT-2TF5 which I picked up at a police auction for $1500. My whole closet acts as a faraday cage. 😀

Whoa, 10,000VA..! *drool*
I think that I could power my PC for a week with that after the power goes out!

(Wait, scratch that, the VA rating is for the output capacity of the inverted, the runtime is a factor of battery capacity. Ignore my technically-incorrect stab at humor. 😛 )

Right. That's why you might see a 420, 500 or 650VA all with the same 12V 7Ah battery inside. 😉

 

[jonnyGURU]

Originally posted by: bfonnes
The reason why people go as high as 500+ watts is completely because of overclocking...

Really? I didn't know that's why I did that. 😕

I know you didn't mean that literally. It just came out sounding that way. 😀

 

[southnjess]

True.

i still have my powerman 350w one and it runs all my upgrades i have done inc my 6800gt.

 

[Acanthus]

My 400w Antec Truepower could not handle my current rig, i had to upgrade to 550w.

P4E 3.0 @ 3.9ghz
1GB OCZ PC4400 Gold
Abit AG8 Motherboard
Leadtek 6600GT HD-VIVO
250GB WD SE
Lite on 48x CDRW
Integrated Sound and LAN

 

[silverpig]

I have a 480 W Antec but that's only because they were sold out of the 430 W Antecs, and the next lowest they had was a 300.

 

[Matthias99]

Originally posted by: Acanthus
My 400w Antec Truepower could not handle my current rig, i had to upgrade to 550w.

P4E 3.0 @ 3.9ghz
1GB OCZ PC4400 Gold
Abit AG8 Motherboard
Leadtek 6600GT HD-VIVO
250GB WD SE
Lite on 48x CDRW
Integrated Sound and LAN

(emphasis added) That might have *something* to do with it. That's not exactly a "standard" configuration.

How high did you have the voltage on that CPU? A P4E 3.4-3.6 at *stock* voltage is pulling over 100W by itself. If you upped the voltage even a little, you could easily be pulling 150W (mostly on your +12V line) for just the CPU.

 

[jonnyGURU]

117.6 to be exact. That's 9.8A load on the 12V rail for the CPU alone.

But I didn't even touch on that post since there's no such thing as an Antec TruePower 400W (380W or 420W, but not 400W.) I figured there was some smoke being blown somewhere up a certain biological orifice. 😉

 

[bfonnes]

nvm bad post

 

[kextyn]

I have no doubt that my 400W Fortron Bluestorm can handle my system and it runs quiet and cool. But if and when I add watercooling and more hard drives I will most likely put a second PSU in my system just for all the accessories (CM Stacker case).

 

[Acanthus]

Originally posted by: jonnyGURU
117.6 to be exact. That's 9.8A load on the 12V rail for the CPU alone.

But I didn't even touch on that post since there's no such thing as an Antec TruePower 400W (380W or 420W, but not 400W.) I figured there was some smoke being blown somewhere up a certain biological orifice. 😉

It was an antec 400w smartpower. I upgraded to a 550w Truecontrol, so i got smart power and true control mixed together 😛

The CPU voltage was 1.41v, so yes, it was a lot of power draw.

Edit: there is a current post in the OC forum about my resorator install if you think im blowing smoke 😛

 

[jonnyGURU]

I don't really think you're blowing smoke. That's why I put the winky in there. 😉

But you are a prime example of someone who needs power. That SmartPower is only capable of 18A on the 12V rail. You're probably using half of that for your CPU alone!! 😀

 

[Bonesdad]

Originally posted by: slash196
A PSU is an investment, just like a case. You'd like to buy a good, quality PSU that you can use through several builds.

A good quality PSU doesnt mean one with 550 watts. It means a stable, EFFICIENT, PSU with enough power to run all of your components. I will be buying a Seasonic 400W PSU with my A64 with 4 drives, a 6600GTand 1GB of memory. I have no concern at all for stability and none for the quality of this PSU.