I have over the past few weeks been looking very closely at power supplies with the eventual aim of writing reviews for the Street.

I have come across the OCZ Gamexstream 1010 Watts and I think to myself why?

Please correct me if I'm wrong, but in these days of energy efficiency, global warming, etc., why would anybody need a power supply of over 1kW? The trend these days amongst the majority of developers/manufacturers is to design hardware with power consumption in mind and I can only see a performance to electrical power ratio if not falling at least staying level. So why would anybody feel the need to buy a power supply that is capable of supplying the equivalent of a one bar electric fire?

Take my system for example. Although not a top of the range system I like to think it is fairly powerful. The most I have ever been able pull from the mains supply is 180W. (Thats with orthos and 3dmark06 running at the same time!).

Does anybody out there have a system that really needs 1kW and how do they justify it?

Regards

Paul

I've seen up to 1.6KW PSUs; the lowest rated PSU recommended for TRI-SLI is a 1KW Corsair, but 1.2KW is more the norm

Radodrill

I'd love to test one of the 1.6kW supplies and see how it performed on this load 24/7. I can appreciate the need for initial high power at switch on but even a tri sli system would, I'm sure, be pushed to need even half this power once running. I'm glad I'm not paying the electricity bill!

Regards

Paul

I just bought EZCool 1050w because it has four +12v rails, two give 20a and the other two give me 36a, which is needed for some vid cards.

Mostly because it features Green Power >= 80% Active PFC: Saves over 80% power usage (optional)

This card actually saves more engergy than my old 500w and 750w PSU's.

So far so good.

thereaper

Could I just make the point that on the figures you are quoting for the 12V lines that would be 1344W. There will be combined limits on your 12V power supply outputs.

Power factor correction will not save you any money on domestic supplies in the UK. Large industrial users are the only ones charged more if their PF slips below a certain value and they benefit from using power factor correction.

Regards

Paul

i have the GameXstream 700, and its not like the PSUs consume that much power all the time. Granted, my results are purely based on the LCD readout of my APC 1500 UPS, but idle power usage for the full system including monitor is around 180w, with full CPU load being about 230w. The most I have ever seen it was about 260w.

I bet you'd like to try out a 1.6KW PSU just as much as I'd like to try a pair of 9800GX2s

I've got a 1KW PSU in my rig, but I have no Idea how much of that is actually under under full graphics load.

I'm not that good with electrics etc, how does this work? "the 12V lines that would be 1344W".

I need to learn more about volts and watts consumption.

Cheers mate.

P = V * I

P: power in Watts
V: Voltage in V
I: Current in Amps

in your case, P = 2 * ( 12V * 20A ) + 2 * ( 12V * 36A ) = 1344W

Although this holds true most all the parts of a PC the only exception seems to be video cards....the more intense they get the more power hungry they become....

If it we didnt need those power hungry video cards we could still get by with 300watt PSUs...everything else is way more efficient than yesteryears parts were and consume about 1/2 the voltage of parts only 2 years ago..well maybe 3 years ago...lol

Isn't the wattage being drawn from the socket going to be different anyway? The rated wattage at the 12/5v DC end is one thing, the watts the psu draws from the socket (AC) is going to be different (lower), it's a different circuit.

I may be wrong. Who's testing PSUs? We got something for you to test...

power is power, the voltage is just the carrier; with a higher voltage it takes less current to draw the same amount of power.

Power_out = Power_in - Losses = Power_in * efficiency

If anything the power drawn from the wall outlet would be somewhat higher than the total power used by the system components

That's cool, thanks radodrill, I am understanding it much better now.

Yep, you're actually going to pull more power than the machine uses since about 20% of the power is lost at full load due to heat and other inefficiencies. Thats why most say they are 80% efficient meaning they can turn 80% of the power they pull into usable juice for your PC.

Someone should test how much more power is being pulled out of your wall outlet by one of these 1KW+ psus compared to a 500-700 watt psu.

A good quality 1000W power supply with 80% efficiency when fully loaded will draw approximately 1250W from the mains. The other 250W is lost in the conversion from AC mains (110 or 230VAC) to DC outputs (3V3, 5.0, 12VDC, etc.) and most of it given off as heat.

Regards

Paul

Wow, I never even considered all this before, thanks for open this thread. No wonder my electric bill has gone up.

What if you are only using a total of say a quarter of the power the psu can give and only using one 12v rail, how does that add up in way of power draw from mains?

Looking at your signature I can make an educated guess at somewhere between 400 & 500W on average. I'm not sure what sort of power your two 8800GTS are pulling but I think you will be looking at between 500W and 620W from the mains.

Regards

Paul

The PSU only provides as much power as the system actually draws; the power drawn from the mains is the power used by the system divided by the PSU efficiency.

Numeric example:
say the PSU has an efficiency of 80%, and the current draw on the rails is:
12V1: 30A
12V2: 25A
3.3V: 10A
5V: 10A

the total power used by the system is:
P_system = 12V * 30A + 12V * 25A + 3.3V * 10A + 5V * 10A = 743W

then:

P_mains = 743W / 80% = 928.75W

That's an eye opener. Thanks guys.

I think we all have Tim the tool man Taylor syndrome, more power uuugh!
I think people just want to buy that PSU that will do them for a long time no matter what they add to their rig. A 1000w good brand PSU is a great start in future proofing your rig for what may come in the next 2 years or even longer. With people adding more and more HDD's to their rigs and running 3 sometimes 4 RAID 0 setups, SLI and all sorts of bells and whistles, it makes sense to be a boy scout about your power and always be prepared..lol

So with my GameXStream 700:
12V[1-4]: 18A ea
3.3V: 36A
5V: 30A

P_system = (12V * 18A) * 4 + 3.3V * 36A + 5V * 30A = 1132W
P_mains = 1132W / 80% = 1416W

Whats wrong with this picture?

There is a max on the different circuits. See

http://www.ocztechnology.com/drivers/GameX..._700W_chart.jpg

The 4 - 18 A can only output 680 W total, but only when the total output of the power supply doesn't go above 700 W. Actually is only rated at 700 W, can probably put out more than that but will be stressed, but not 1132 W.

huh... Well, it powers my system, and only uses < 260w at full load (CPU and gfx card). Good enough for me!

Take a look at the spec chart for the GXS 700W:


Each 12V rail is rated for a maximum of 18A or 216W; however, the total combined load on all the 12V rails and the +3V and +5V rails cannot exceed 680W. In other words, the power supply can provide up to 18A on each 12V rail, but is not capable of providing a full 18A load on all 12V rails simultaneously.

Well that makes sense Rado...I never looked at it as a Max wattage produced Like Branjo said, I was future proofing the system. Glad to know that I have that much overhead left!

Glad it makes sense now

The number's I used in this example were illustrative of actual load and are well within spec for my PSU

splahdaw
http://www.newegg.com/Product/Product.aspx...N82E16817101033
2kw psu. :angel:

Yeah and for max output it requires two power cords and a dedicated 20A outlet.

Wow now thats overkill

exactly. i like the second comment. crazy nerds :angel:

I dont get it though... how do two power cords help if they're both going to the same outlet:confused:

especially with ac power....:confused::sweat:

it could be useful if... you went for the skulltrail and did mad oc's and decided to use alot of pelts or something maybe . or used one of those mountain mod dual-computer cases and had dual skulltrails. or just wanted to find a way to kill the power bill:tooth:

One power cord would have required a 20A plug which will not plug in a 15A rated outlet that's commonly used in homes here in the States.

ah. i get it now :angel:

thanks.

not just that, but look at the non-standard monstrous size :tooth:. you have the huge box sitting outside, then it plugs into a cord divider that goes in the psu slot...

That might be a good thing. There is no way the necessary components needed to deliver clean power at that wattage would fit in an enclosure capable of being installed inside the case.

650 bucks! though, for that I would want a coffee maker on the top

Damn thing better please me in bed too!

I love Dale3RIP's review on the power supply. You might be a redneck if you use a 2kw computer power supply to power your backwoods camper

What a frickin' hoot

All I have to say is wtf mate.