Which Power Supply Is Best ????

[PCBONEZ]

Re: Which Power Supply Is Best ????

A 500 watt would be more than you need.
.

[colormebad]

Re: Which Power Supply Is Best ????

Im gona run the one that came with the combo kit...Just looking at others...
What you guys think about this one ? Good specs and a good price...

http://www.newegg.com/Product/Produc...82E16817703028

[c_hegge]

Re: Which Power Supply Is Best ????

^
That ons is excellent (although overkill). You simply can't go wrong with PC Power & Cooling, period.

http://www.newegg.com/Product/Produc...82E16817703035
That one, though is more suited to your power requirements.

[PCBONEZ]

Re: Which Power Supply Is Best ????

When you use too big a PSU the efficiency goes to shit.
.
It's like using a Peterbilt to run get a gallon of milk.
.
Using a 1000 watt when you don't need anything near that will give you great bragging rights among people that don't know their ass from a hole in the ground.
- But why would you care to impress them anyway?
And people that know what they are doing are going to know for sure that you don't.
.

[mariushm]

Re: Which Power Supply Is Best ????

^ You simply can't go wrong with PC Power & Cooling, period.

If I remember correctly, PC Power & Cooling was bought by OCZ.

They're not custom designs anymore, so no point giving them extra credit for that - they're plain oem designs with maybe custom fans.

The MKIII for example is a slightly modified Seasonic SS-600ET platform - the same found in Seasonic S12II Bronze power supplies: http://www.jonnyguru.com/modules.php...tory4&reid=263

So this MKIII 500w one at 80$ : http://www.newegg.com/Product/Produc...82E16817703035
is about the same as this 620w Seasonic: http://www.newegg.com/Product/Produc...82E16817151096

Just 1-2% better efficiency on the mk III, no difference in real world...

The Superflower Golden Green designs are technically better as it's newer design but Seasonic is generally better in terms of quality (soldering of the components, capacitor selection etc)

[ratdude747]

Re: Which Power Supply Is Best ????

iircs, superflower uses UCC and polys for their builds... so i see nothing wrong with their choice in caps.

[dood]

Re: Which Power Supply Is Best ????

I'm watching this thread with quite a bit of interest. I'm getting a computer upgrade for Christmas (Phenom X4), and I'm already running 3 HDs and a beefy video card. I'm a little worried that my 430w supply isn't going to cut it. As it is, I would at least like to have the 2 PCIe power connectors that my video card requires, without having to use a 4 pin molex adaptor like I do now.

So, carry on discussing.... I'm getting some good ideas

[mariushm]

Re: Which Power Supply Is Best ????

Well dood, I have one of those Kill-a-watt meters and I've tested my system...

Q6600 (quad core, similar in consumption to the phenom 2 x4)
4 gb ddr2 (2 x 2 gb)
4 hard drives
1 dvd rw
1 radeon 4850 (newer cards like the 6850 or 6950 are more power efficient)
1 tv tuner (winfast 2000xp expert)

The power supply is Seasonic X-650 which has about 90% efficiency on the 230v here in Europe.

The system idles at 170w so the system itself pulls about 140w from the psu.
When playing games or doing video encoding, it goes up to 270w - so about 250w from the psu.
Basically, on today's computers, about 85% of the load is on 12v so when thinking if a power supply is good enough, you need to look at the Amps it's capable to supply on 12v.

In my case ... 85% of 250w is about 210 watts... divided by 12v.. that's a bit over 17A.
Add about 20% as safety measure and I'm looking at 20A on 12v

Basically, any power supply that can do that is enough for me - 20A is typical for 520-550w power supplies.

I chose x-650 because it's Seasonic, it's Gold (high efficiency) and it has the fan stopped at low loads (usually less than 150w). My system is right there, every few minutes fan starts spinning at low speed for about 20 seconds, can't even hear it.

Regarding video cards, the standards regarding power say that a video card is allowed to take up to 75w from the pci express slot (about 60w on 12v, 10-15w on 3.3v) and video cards are supposed to pull up to 75w from each 6 pin connector (they can go over but it's not recommended).
So basically, a card having 2 6 pin connectors tells you that the video card may use up to 75+75+60 = 210 watts of power on 12v, or about 17a (in reality, most video cards with 2 six pin connectors don't count on the power from the pci express slot, and they use about 160 watts max).

But anyway, let's leave it at 17A - add about 10-15a for the rest of the components and you need a power supply capable of about 30-35A... even the Corsair CX v2 500w is capable of 34A on 12v alone... see the pictures: http://www.newegg.com/Product/Produc...82E16817139027

[PCBONEZ]

Re: Which Power Supply Is Best ????

Looking at mariushm's example with 270 watts being heavy load you want a PSU such that 270 watts is around 80% [or less] of the PSU's max.
270w/0.80 = 337.5w [That's the minimum you'd want for total watts.]

- BUT.
Ideally you want the max of -EACH- rail at 20% [or more] less than their max [for safety margin] so you have to figure out your loads rail by rail.
- Having a PSU with 200 extra -total- watts won't do you any good at all if it doesn't have enough amps on +5v to run the system.
- Multiple +12v rails doesn't do you any good either if -any- of them don't have enough amps for their load.
.
All the rails on PSUs don't usually match-up perfectly to the system needs, so, by the time you get enough amps on -all- the rails you are usually something like 100-150 watts over what the minimum total watts is.
[That's where going only by those on-line PSU calculators can screw you hard.]
.

[Scenic]

Re: Which Power Supply Is Best ????

I'm watching this thread with quite a bit of interest. I'm getting a computer upgrade for Christmas (Phenom X4), and I'm already running 3 HDs and a beefy video card. I'm a little worried that my 430w supply isn't going to cut it.

I've been running an overclocked Core 2 Quad Q6600 2.4 @ 3.6 with a Geforce GTX260 (rated at 171W at full load) with a stack of HDDs and lots of tidbits on a Seasonic SS-430GB (S12II-430) for ages.. no probs whatsoever.
And it's the older S12II version/revision (no 80+bronze)

A bit of clever upgrading got me a noticeably faster graphics card that uses less power than the GTX260 (a HD6870 rated for 151W max.)

A HD6850 for example clocks in at "only" 127W, which is amazing considering the performance of that card compared to other AMD/ATI's or nVidias in the same performance-class.
GF460, GTX465, GTX560Ti, HD5830, HD4870/4890 ... they all use considerably more power (GTX465 = 200W, HD4890 = 190W) while being slower.. lol

This gfx card chart is in german, but most of the time it doesn't really matter. Haven't found a more complete or consistent list yet. And they list the power usage for every card too (if it's known)
It helped me out countless times to find my way in the jungle of cards out there..
http://pc-erfahrung.de/grafikkarte/v...rangliste.html

[mariushm]

Re: Which Power Supply Is Best ????

The load on the 3.3v and 5v is pretty much constant these days.

5v is basically used by hard drive electronics boards, by pci cards (about 5-10w each) and some onboard devices like sound cards, additional usb ports etc.

3.3v is mostly used to power the memory modules these days, as far as I see, and just a bit by pci express cards and besides that sata drives are supposed to use it but most generate the voltage from the 5v line as they want to be backwards compatible with the old hard drive power connectors that only have 5v and 12v.

So while there is some use of these voltages, it's very small and relatively steady - that's why I made a generalization and said 85% of power is on 12v and the rest on 3.3v and 5v.

Most new psu designs do about 20-25A on both 3.3v and 5v but combined only about 150w - that's quite more than what the average computers uses these days, which is 5-10a on each of these, so in my opinion you don't have to worry about it.

My 270w max is from the wall, and I know Seasonic x-650 has about 92% efficiency at about 550w and drops to about 86-88% at 300w.
So if the system pulls 270w at the wall, that means that the total power requested by components is much less:

? watts --- 88%
270 watts -- 100% (assuming the psu is 100% efficient)

? watts = 270 x 88 / 100 = 237.6 watts.

So my system will demand 237.6w no matter what psu you use. My X-650 will draw 270w from the wall at 88% efficiency, a cheaper 80% efficiency psu will appear as requesting 285 watts from the wall.

Now this 237.6 watts of power requested by the system is on ALL 3.3v + 5v + 12v rails.

I'm generous and give 20% of the power to 3.3v and 5v rails which ends up to about 50 watts - assuming the rails are evenly loaded, we're looking at 25w/3.3v = 7A on 3.3v rail and 25w/5v = 5A on 5v.

Any brand name power supply nowadays is capable of delivering about 20A on 3.3v AND 5v with the mention that together they're generally limited to 100-150w of power. So for most modern systems, we really don't have to be concerned about 3.3v and 5v rails, as the power supply can do about 3-4x as much as systems use.

I would only start to be concerned about 3.3v and 5v rails on the new systems with LGA2011 sockets and 6-8 memory slots but I have a suspicion those motherboards use 12v for powering memory as well.

Anyway, going back to our values... 237.6 watts in total... 20% on 3.3v and 5v... we're left with about 180 watts on 12v, which ends up to 15A of 12v. Giving it a large 20% safety margin, we come to the conclusion that a power supply with a minimum of 18A on 12v would be enough for this system.

Now we get into the whole single rail vs multi rail.. Single rail psus are straight forward, all the power is on a single rail, it doesn't matter how you connect devices.

With multi rail power supplies, the power supply can deliver a constant amount of power for hours and can also deliver more if needed on a particular rail with the condition that the other rails are loaded to a lower percentage.

Looking for example at this power supply (which is quite good btw ignoring the brand name):

http://www.newegg.com/Product/Produc...82E16817194085



We can see this 500w psu has 3 rails, each rated for a maximum of 25A (300w) so you'd think it can do 900 watts on 12v. But, the manufacturer is honest and says below the power supply can do only 41A on 12v, or 492 watts.
This is OK - my system only needs 18A so this psu is quite good with 41A of power.

Now with this particular power supply there's a "gotcha"... you can see 100w on 3.3v and 5v and 492w on 12v is more than 500w. This tells you that the 3.3v and 5v rails are generated from the 12v rails using a DC to DC transformer.
So, when knowing my system uses about 50 watts on 3.3v and 5v and knowing that such dc to dc converters have about 85% efficiency, I know this power supply's DC to DC converter will need about 70 watts to generate my 3.3v and 5v requirements or about 6A of power from the 12v rail.

Now the 41A of 12v power goes down to 41-6 = 35A of pure 12v power. Almost double the power my system needs on 12v. Even in the worst case scenario where you'd use 100w of 3.3v and 5v on this power supply, you'll still have about 30A of 12v power.

Here's for example comparison with the much cheaper and lower efficiency Corsair CX v2 500w :



This one has separate transformers for 3.3v+5v and 12v... so they're separate.

[PCBONEZ]

Re: Which Power Supply Is Best ????

Sort of.
3.3v and 5v are basically to power IC chips including the RAM and on add-in cards [beyond the obvious OB chips].
.
PCI [including PCI-E] specs call for availability of 2 amps per slot for add-in cards.
5 slots is not uncommon so there goes 10 amps right off the top.
.
RAM can be powered by 5v or 3.3v but it's usually both, just not at the same time.
There's a circuit Intel sometimes calls 3.3vsb that basically auctioneers RAM power from both 3.3v and 5v - but all boards don't necessarily have that.
So unless you've traced out the power plane on the board you should 'do the math' assuming RAM loads both 3.3v and 5v because you dunno which it's on.

With 10 amps reserved for slots adding 5 drives pretty much sucks all available +5v up if you only have 20 amps to start with.
If you intend to use more than about 3 drives it's a good idea to beef up the +5v amps on the PSU.
.

[mariushm]

Re: Which Power Supply Is Best ????

See... you're confusing people.

You're saying it as if the motherboard actually uses 2A of 5v power for each PCI slot no matter if you have something connected in it or not.

No, in fact some cards use less, some use more - each card is allowed to use up to 25 watts but the reality is on modern systems the average user barely uses 2 pci cards (tv tuner and maybe a sound card or a firewire/extra sata controller) and these types of devices don't use that much power.
How much exactly is each one using? They're keyed to say they use 7.5w, 15w or 25w - I'd say most don't use more than 10 watts.

It's also relatively uncommon to get more than 3 pci slots nowadays, on today's motherboards you barely see 2, so I'd say my estimations are more realistic for computers of 2010-2011.

As for the PCI Express, it's limited to 3.3A on 3.3v or about 10 watts. How many pci express cards is the regular user owning, besides the video card? Almost none.
How many pci express cards even use this line? When the modern cards idle at below 10 watts you can be sure they don't use 3 Amps on 3.3v rail.

Regular hard drives don't use much 5v power ... the 3TB Seagates use 0.6A on both 5v and 12v: http://www.newegg.com/Product/Produc...82E16822148736 Check the pictures, it says on the label.

The SSD drives do use more power... up to 8 watts when writing, and I think they only use the 5v line. For all intents and purposes they can be treated as two regular drives.


So for regular user, and I'm exagerrating the numbers:

[2 pci cards x 3a each ] + [3 hard drives x 0.75a each ] + 4A various stuff on motherboards = 12 A on 5v.... just a bit over half of a power supply's capability.
[2 pci express x 3.3a ] + 6A various stuff on motherboards = 12 A ... still about half.

So for the average user... it's valid what I said... you don't have to concern yourself about the 3.3v and 5v lines, there's enough room there.

One thing that's important to mention is that lots of brand name power supplies are underrated, to get the 80+ efficiency numbers and for other reasons... these psus can do MORE than what they say on the label.

For example, as I relate to Seasonic X-650 because I own it, here's overload test for it: http://www.hardwaresecrets.com/artic...y-Review/837/8 - it started to show excess ripple at 793 watts...

[PCBONEZ]

Re: Which Power Supply Is Best ????

See... you're confusing people.

You're saying it as if the motherboard actually uses 2A of 5v power for each PCI slot no matter if you have something connected in it or not.

No that's not what I said at all.
.
What I said is the spec calls for that much to be available.
If you have the slot you should get enough PSU to power the slot in case you ever want to use it.

You'd have to be a moron not to.
Why would anyone want to be in a position where they have to upgrade their PSU just to add another add-in card.
.

[PCBONEZ]

Re: Which Power Supply Is Best ????

Yeah, and some DVD Burners pull over 2 amps on +5v.
I said 'drives', not 'hard drives'.
.
Even still there certainly are hard drives that pull close to an amp on +5v.
My Raptors pull 0.9 amps on +5v and some of my RE series RAID drives pull 0.92.
- And that's just looking at what's handy right now.
15k RPM drives [SCSI or not] probably pull even more.
.
If you want to limit what you can use for drives and slots by not leaving enough room on the rails then you go right ahead.
.
A good builder would ensure there's enough PSU for anything that might come up in the life of the system.
.

[colormebad]

Re: Which Power Supply Is Best ????

See' i build drag race motors for a living & do some electronic & ignition work also...I see guys all the time' everytime that add a new box' they need a better amp alt' or a bigger battery...Thats why i want a good P/S to start ' when i start adding on' dont wont to have to keep buying a bigger P/S...
I like this one below' I just talked to someone thats running 3 of these and rated them realy high...

http://www.newegg.com/Product/Produc...82E16817703028

[mariushm]

Re: Which Power Supply Is Best ????

Sorry about the drives/hard drives part. I agree with you on the "specs calls for that much to be available", you do have a point.

However, the real world is full of compromises and it's not just the psu that has issues.

Each PCI connector is rated for 25 watts maximum, yet with 5 pci connectors you'd have 125 watts or 25A solely for pci slots. It doesn't make sense to design a power supply for that much wattage on 5v.

Each PCI-Express x1 connector is rated for about 25 watts and each pci Express x8/x16 is rated for about 67 watts at 12v. There are now motherboards with 4 pci express x8 or 16 slots -do you think the motherboard manufacturers made the boards capable of 67 x 4 = 268 watts of power through the board? The 24pin connector was rated for something like 125 watts @ 12v and the 4-8 pin CPU connector is already stressed enough.
Very few of today's motherboards would be capable of powering all 4 pci express slots, yet they're not considered faulty.

Three, maybe four years ago, I had a friend in the university campus that had to get another power supply because the 400w one he bought only had 12A on 12v and the 6 drives he had were triggering the psu's protection at boot, because of the spikes of the motors coupled with the consumption of the P4 cpu. Was the psu faulty? Absolutely not.

You want high efficiency in psu, you make them with dc-dc converters, allowing up to the maximum the psu is rated for on 12v... but these converters have some limits...20-25a on 3.3v or 5v.

This is a sensible value, more than enough for average users and it's not a flaw of the power supply.
If you do need to use 3 pci cards or more, if you use more than 5-6 hard drives, then you should think about a more specialized psu.

A good builder won't pick a psu for anything that might come up - if that's the case all computers would have 1000w power supplies because the user may buy 2 gtx 580 or 2 x radeon 6990 (350w each).

A good builder would pick a psu that would be rated for 150% the maximum load of the system when playing or doing something intensive, so that the efficiency remains high throughout its use and there's some room for upgrades.

[PCBONEZ]

Re: Which Power Supply Is Best ????

See' i build drag race motors for a living & do some electronic & ignition work also...I see guys all the time' everytime that add a new box' they need a better amp alt' or a bigger battery...Thats why i want a good P/S to start ' when i start adding on' dont wont to have to keep buying a bigger P/S...
I like this one below' I just talked to someone thats running 3 of these and rated them realy high...

http://www.newegg.com/Product/Produc...82E16817703028

Yeah, I built street rods on the side for about 20 years.
.
I don't think I'd put a drag motor in a school bus though.
.

[dood]

Re: Which Power Supply Is Best ????

So, I'm a bit confused. I don't see how what a computer draws from the outlet makes any difference. When you use the Kill-a-watt, you're talking 270w @ line voltage. That's NOT the same as wattage @ lower voltage, if I understand correctly. So, 270w at the wall is not what your PC is drawing on the 12v rail (if we simplify it and constrain everything to one rail). Am I mistaken here?

[Scenic]

Re: Which Power Supply Is Best ????

For the system he posted, and because he said he's not a gamer (onboard video), i'd say get a solid 500-600W and it'll handle everything he could possibly upgrade on that system, except a high-end graphics card for gaming.

I don't know anything about the PSU that came with the kit (link), but if it's honestly rated, it's fine the way it is IMHO. (i.e.: overkill for the current sys, having lots of headroom for upgrades later on)