Silly power requirements, an over hyped myth?

[Nullvoid]

Is the wattage on a PSU what it can handle from the mains or what it can push out once the AC it draws is turned into DC? I think it's the latter. Someone correct me if I'm wrong, but putting a wattage meter on the mains won't tell you what the PSU is putting out in DC form...

You're right, it's the latter. To convert the figures you get from one of these watt-meters you need to know the power supply's efficiency at whatever wattage you're reading. So if our hypothetical system was showing 500w on the watt-meter and the supply just happened to be rated for an exact 80% efficiency at that wattage, the supply would actually only be providing 400w to your system. Since we can never know the efficiency with that much detail (unless we decided to have an array of multimeters/clampmeters monitoring every single lead in use on the power supply), it can only ever really be a rough guideline.

 

[Nullvoid]

Don't take it for granted, some of the PCP&C have terrible efficiency even though they cost a fortune.

Yes, you don't buy a pcp&c for it's amazing efficiency, you buy it for its rock-solid voltages and the handy function its fan provides of drowning out any nagging from passing family members.

I did get a bit carried away with the toughpower example didn't I. They are more of a model of how every top of the line psu should aspire to be, rather than an example of how every top of the line psu currently is.

 

[Jokester]

Zalman ZM-MFC2 Multi Fan Controller

Got mine sitting on my desk, going to see how high I can get the power reading .

Jokester

 

[david25]

Final word on this?

http://www.behardware.com/articles/670-4/pc-s-actual-power-consumption.html

384.7 watts in idle
687.6 watts in load for a....

- ASUSTeK P5N32-E SLI Deluxe (nForce 680i SLI)
- Intel Core 2 Duo QX6700 @ 3.2 GHz @ 1.5V
- Ventirad Scythe Infinity
- 2 x Albatron GeForce 8800 GTX
- 4 x 1 GB DDR2 800 @ 2.25V
- 2 x Western Digital Raptor 74 GB
- Samsung 250 GB + Maxtor 250 GB
- Lite-On CD-RW 48x
- Enermax 120mm at max
- Creative Sound Blaster Audigy

 

[chaparral]

Got mine sitting on my desk, going to see how high I can get the power reading .

Jokester

Everytime i have done my 3dmark06 power runs with my system overclocked to the max i have always forgot to take even one look at the power meter

 

[TheSwede]

Zalman ZM-MFC2 Multi Fan Controller

That one is on my shopping list when I am going to upgrade! Come on July 22nd!

Cheers
Tom

 

[Corasik]

One thing to remember when measuring the load on the AC side, is most PSU's have some fairly hefty capacitors in them, which actually store a small reserve of power, infact I've had short power cuts, where the lights went out, but the PC kept running without a hitch!.

So the 'Average' power your PC might use measured by the power meter is a fair 'baseline' reading, but it could well have brief peaks of power draw which could stress an underpowered PSU to the point the PC becomes unstable.

So I would always want some 'spare' above and beyond the measured load. This also allows for PSU ageing.

However, I tend to agree with the original poster, that silly power requirements are an over hyped myth. My own PC, [email protected], with a Geforce 7900GTX only manages to draw just over 100w when idle, 180w when gaming or running dual prime, and I did manage 220w with 1 prime, and 1 game keeping both GPU and CPU busy. Yeah yeah, I need a better GPU.. but if I had believed the hype, I'd probably be running a 600W PSU. As it is, my 500W PSU has a very easy life .

 

[Jokester]

Idle

Load (3dmark06 + 3 Primes)

Now to start overclocking .

Jokester

 

[JIM_BOB7813]

Idle


Load (3dmark06 + 3 Primes)


Now to start overclocking .

Jokester

Specs?

 

[Jokester]

QX6700, 8800 Ultra SLI, 680i.

Jokester

 

[Tom|Nbk]

What's that monitoring thing you have Jokester looks rather nice.

 

[Jokester]

What's that monitoring thing you have Jokester looks rather nice.

Same as chaparral:-

Or you could buy a Zalman ZM-MFC2 Multi Fan Controller http://www.overclockers.co.uk/showproduct.php?prodid=BB-000-ZA&groupid=701&catid=57&subcat=189

Which has
- Real-time display of overall PC power consumption

has got. Going to see if I can max it out (800W) .

Jokester

 

[Tom|Nbk]

How does this monitor power consumption?, I think ill have to get one of those I like it a lot

 

[Jokester]

It's got a current meter that you plug in line with the mains lead, then a cable you plug into a back plate and on to the front panel.

Jokester

 

[chaparral]

Idle

Jokester

367watts at idle....Thats more then what my system uses most the time underload (unless am really stressing it)

This is one thing that worrys me about upgrading to an overclocked Quad core cpu..(electric bill)

 

[Tom|Nbk]

Just ordered one of those controllers, I'll have to get round to selling my old one now . 30 quid seemed a bargain.

 

[Scougar]

However, I tend to agree with the original poster, that silly power requirements are an over hyped myth. My own PC, [email protected], with a Geforce 7900GTX only manages to draw just over 100w when idle, 180w when gaming or running dual prime, and I did manage 220w with 1 prime, and 1 game keeping both GPU and CPU busy. Yeah yeah, I need a better GPU.. but if I had believed the hype, I'd probably be running a 600W PSU. As it is, my 500W PSU has a very easy life .

What is interesting is that I put in my rig onto the extreme power supply calculator. It came up with 416w recommended. I tried it with Crossfire 1950xt's and it suddenly recommened 508W (and I'm getting a 520W lol). If I overclocked from 2600 to 3200 i suddenly get recommended 556W.

I seriously doubt I will be running the dvd burner and gaming and getting full strain out of the system at anyone point.

Seems a little high to me.

Matthew

 

[ChrisD.]

I need one of them Zalman thingies!

 

[Jokester]

3GHz, quad Prime, stock volts.

Jokester

 

[BassPunk]

3GHz, quad Prime, stock volts.

Jokester

lmao

now that is why psu's need to be able to handle 1kw