power supply's ,whats up?

[Daveroo]

hey all..
ive been looking and i see most new PCs ,i only look at "gaming desktops",,,most have 450watt PS,my currant dinosaur has a 700watt unit in it.i was told by a guy here in town.builds custom gaming machines...he told me you dont need more than 450watt and it keeps the CPU cooler..which doesnt make sense to me.

i would think that more power in the power supply would leave excess power to help the pc with background programs not turned off ...


the main thing im wondering..can i order the pc with the $0.00 cost on the 450w and replace it with my 700w without big trouble?

[JimmyRFR]

I had a 450W power supply on my old PC for a lot of years, with no issues. When I upgraded my PC last year, I opted for a slightly larger supply; I now have a 550W in there. However, really, the only reason I felt a little uncomfortable with the 450 was because I was also installing a 780ti video card.

Generally, unless you have a very good reason for a large power supply such as demanding video cards, or perhaps two video cards running in SLI, you really have no valid reason to go to something as large as a 700W, in my opinion.

And considering that they really aren't that expensive, or hard to upgrade, you could always go bigger down the road if need be.

That said, it's not all about the wattage; I would stay away from really cheap / budget power supplies. I've had good luck with Corsair. My current power supply also has modular cables, which means I only plug in the ones I want to use. Keeps the case cleaner, which equals more air flow, which equals cooler temps.

[Blackbird686]

What Jimmy says is true... as well... componentry within a PC had become a lot more efficient, using less power to produce the same if not better results. Running cooler and drawing less form the PS.
By today's standards... 450 Watts is a good strong power supply for a mid to upper level machine. Should be just fine with most that you would throw at it.

BB686

[hairyspin]

Surely it's a matter of arithmetic? Some sites have calculators where you can enter motherboard model, processor, memory, HDs, video card etc and it spits out a power requirement. If your kit needs 500W you'd be daft to get a 400W PSU! Type computer power calculator in Google and you'll get a bunch of hits. Then get a decent-quality one of the needed size.

[Jafo]

Make sure you have 'headroom'. It is bad policy to be essentially running a PSU near to or at max load as with age its output will diminish and 'economies of scale' will see its cooling being 'only sufficient', not 'efficient'.

My machine isn't your 'average'....it's more genuinely 'high end' and I chose a Corsair ASX1200I Platinum Certified [which is modular] and mostly doesn't raise enough of a sweat to even see its cooling fan start. In other words it's silent.

Headroom will also enable those potential upgrades/addons you do to stave off forking out on a complete new system.

As others have said, there are 'calculators' available...and some allow for age/deterioration which tends to bump things up quite a bit more than something the size of a 450.

Bottom line is very much the bottom line....buy quality over all else. When a PSU fails it usually takes down the entire system...

[rcbarend]

hey all..
ive been looking and i see most new PCs ,i only look at "gaming desktops",,,most have 450watt PS,my currant dinosaur has a 700watt unit in it.i was told by a guy here in town.builds custom gaming machines...he told me you dont need more than 450watt and it keeps the CPU cooler..which doesnt make sense to me.

You are right; that doesn't make sense.
I'm afraid many people (including sales people) focus too much on the max. power (Watts) of a PSU; what's much more important in how a PSU behaves in terms of Voltage stability, etc. at high loads.
Meaning that, besides realibility of used components, fan noise, and so, a 400 Watt PSU of one brand may out-perform a 600-700 Watt PSU of another brand.

As usual, you pay for quality ....
Unfortunately, the PSU is probably the most under-rated component of a PC; meaning it's often chosen as the last item to balance the budget....
And a cause of many stability problems (even if you don't over-clock your system)

Rob

[dharris]

This is the calculator that I use, you may be surprised how much you need,,, http://www.coolermaster.outervision.com/

[Ian Warren]

Guys guys , Dave, this will make you laugh I was told by a person , "I put a larger power supply into my computer and it has not seemed to make it faster" .. It was a mission to try and explain .... It was bloody funny

[dharris]

Weellllll I bought the bronze edition 'cause it went with the general color scheme inside the case!

[Ian Warren]

Weellllll I bought the bronze edition 'cause it went with the general color scheme inside the case!

Gotta be IN with the IN crowd , some off the stories I have heard really leave you

[Daveroo]

my concern isnt ..mo power..mo power.....

i just want to make sure that it has enough to run what its supposed to under the load of FSX.SE ..or the train sim...et all...

[Ian Warren]

I have 650 watts , 5 independent hard drives, it did require a little extra wiring , this was due to if had graphic/art programs open and working between the 3 maybe 4 it decide to hang , If I have done a little work taking a break, thing will do silly thing, realistically I think 450/500 would suit you no problems.

[Ivan]

Here's my take on Power Supplies FWIW.
Keep in mind that I have not pieced together a desktop system with separate components since my AMD Athlon 1.33 GHz Thunderbird, so the specifics may be a bit dated.

The 1.33 GHz Athlon was an odd chip for the time because it drew a LOT of power. I believe the processor itself could draw up to 150 Watts of power.
At the time, there were power supplies that were certified or approved for use with this processor. They ranged from a low of 250 Watts to 500 Watts.
Why the wide range?

Well, Power supplies actually supply quite a few different voltages and different Amperes at each voltage.
The following numbers are made up, but will hopefully illustrate my point.
Typical Voltages are:
+3.5 Volts
+5.0 Volts
- 5.0 Volts
+12.0 Volts
- 12.0 Volts

Each voltage is meant to drive specific components of your system.
The CPU I believe used +3.5 Volts and +5 Volts
Memory used +5 Volts
Motors such as on Hard Drives and Floppies (Yes, I had those) and CD / DVD drives typically use +12 Volts.

The problem is that with some lower quality power supplies, if you draw pretty close to the maximum Amp rating, the voltage might not remain constant; If you have a 12 Amp limit at +12 Volts and try to draw 11.9 Amps, you are still in theory within the limit, but you may find that your voltage has actually dropped to +11.3 Volts instead of 12.
This is why I believe that only SOME power supplies at a certain Wattage were approved for use with the very demanding Athlon Thunderbird.

Lets say your PS is rated at 450 Watts and the details on the sticker say the following:
+3.5 Volts------------------25 Amps (87.5 Watts)
+5.0 Volts------------------33 Amps (165 Watts)
- 5.0 Volts------------------10 Amps (50 Watts)
+12.0 Volts-----------------12 Amps (144 Watts)
- 12.0 Volts-----------------0.1 Amps (1.2 Watts)

Total is 447.7 Watts available so this is a "450 Watt" Power Supply.

I first started off with a power supply of around 350 Watt which was approved for the Athlon Thunderbird.
Things were interesting because it usually ran without a hitch but sometimes would freeze for no apparent reason.
A Reboot would cure things though.

One of the choices I had made when building this system was to load it up with DDR memory instead of standard for the time. I don't know if that was the real problem or perhaps it was my Radeon graphics adapter, but SOMETHING was not happy until I swapped in a 450 Watt Power Supply.

As for making the processor run hotter with a larger power supply, keep in mind that the typical computer power supply is not terribly efficient. I remember the typical efficiency was about 80% which meant that an additional 1/4 of the energy that the power supply put out was being dissipated as heat within your chassis. The actual power supply I ended up using was a "High Efficiency" version which was all of 85% efficient if I recall correctly.

Hope this makes sense.
- Ivan.

[Jafo]

Corsair 80 PLUS Platinum certified power supply units are guaranteed to operate at a minimum of 92% efficiency at 50% load on 110V circuits, and at least 94% efficiency at 50% load at 230V. Superior efficiency means lower operating costs and less heat generation. All Corsair 80 PLUS Platinum certified CPUs incorporate our Zero RPM Fan Mode technology, so the fan doesn't even spin until it’s needed.

I'm on '230v' [240 - in Oz] so can expect minimum 94% efficiency at 50%...and as mentioned doesn't raise a sweat so is silent.
It's also in a Thermaltake Level 10 case so is totally isolated from the rest of the components even if it were to think about being warm.



You get what you pay for....

[JimmyRFR]

I have to correct my earlier post; I have a 650w Corsair, not a 550w. At home now, so was able to check rather than go off of my (often faulty) memory!

However, as I mentioned, my upgrade on the power supply at my last pc build was more to do with concern over the power draw from my 780Ti than anything else. That, and as a photographer, I have 7 hard drives just on this desktop alone.

I've been happy with my choice of supply; very stable power and virtually silent (well, it is silent compared to the 780Ti when that thing starts to spin up).

I have had a power supply 'go' on me before. It didn't take anything else with it, but it did make one hell of a loud POP when it quit!

[Dimus]

This is a good PSU calculator:

http://www.extreme.outervision.com/p...ulatorlite.jsp

More power will not hurt at all, except in buying price. Less may hurt. It is good to have a margin. However, it is true that newer components are less power hungry, like the newer Nvidia cards. As many pointed out always go for a good brand and avoid the no-names. Corsair has also served me well after changing two no-names.

[stansdds]

I think the reason we see lower wattage power supplies in new computers is simply because the new hardware is more energy efficient and requires less power than the hardware of a few years ago.

[Bjoern]

The only thing you need to look out for on a PSU is an 80%+ efficiency rating, 30+ A on the 12V and about 500W (or slightly less, with the most current hardware).

Unless you're running SLI/Crossfire. That complicates things.

[fxsttcb]

I think the reason we see lower wattage power supplies in new computers is simply because the new hardware is more energy efficient and requires less power than the hardware of a few years ago.

I believe you are right.
No rating is correct for every machine. Us folks that build custom gaming rigs use the GPU mfg's reccy + 10-15%.
Add more juice for h2o pumps and high current fans. Those calculators do come pretty close...Don

[fsafranek]

Also, and maybe it was said above, but get one that is modular. Meaning only those wires actually going to a component get plugged in the power supply.
That will make your cable management much easier. That keeps things tidy and improves air flow.

[Chris Sykes]

Well this will rumble the feathers, I use a 1300w PSU, yes you read that correctly 1300w! That's because I don't run a basic system, 5+ HDD's, 16gb RAM, 4gb 770 GTX and a quad over clocked to 4.3 it needs over a 1000w PSU! Also take into consideration that normally a PSU runs at better efficiency when NOT maxed out, and they run less efficient maxed out. Always wise to add extra watts as this gives you room to add more to the PC and also the PSU capacitors degrade over time. This is where a low spec'd PSU starts to hurt you and your system.

[Jafo]

Well this will rumble the feathers, I use a 1300w PSU, yes you read that correctly 1300w! That's because I don't run a basic system, 5+ HDD's, 16gb RAM, 4gb 770 GTX and a quad over clocked to 4.3 it needs over a 1000w PSU! Also take into consideration that normally a PSU runs at better efficiency when NOT maxed out, and they run less efficient maxed out. Always wise to add extra watts as this gives you room to add more to the PC and also the PSU capacitors degrade over time. This is where a low spec'd PSU starts to hurt you and your system.

Or you could pop back up the page and see comment #5....

My specs are a "wee bit" beyond those you quoted ...