PC Power Consumption: How Many Watts Do We Need?

[Zenbaas]

I already posted this in another thread but I though it was interesting enough to warrant its own thread. We always seem to overestimate how much power our systems need(which isn't a bad thing BTW) to power them when they actually need considerably less. Here is an interesting review on the matter from XbitLabs Enjoy.

First Page
Conclusion


High-End Gaming PC 1

Next goes a top-end and expensive gaming system based on Intel’s newest processor Core i7.

* Processor: Intel Core i7-920 (2.66GHz)
* Mainboard: Gigabyte GA-EX58-UD3R (iX58 chipset)
* System memory: 3x1GB Samsung (PC3-10666, 1333MHz, CL9)
* Hard disk drive: 1000GB Seagate Barracuda 7200.11 ST31000333AS
* Graphics card: PCI-E 896MB Leadtek WinFast GTX 260 Extreme+ W02G0686
* Optical drive: DVD±RW Optiarc AD-7201S
* System case: IN-WIN IW-J614TA F430 (550W)

If you ask at a hardware forum about the power consumption requirements of this configuration, you will most likely be advised to get a 750W power supply at the very least. Will the 500W PSU cope? Let’s see.

High-End Gaming PC 2

The most serious gaming station is the same as in the previous section but the graphics card is replaced with a dual-chip ASUS ENGTX295 (i.e. GeForce GTX 295). Here is the full configuration:

* Processor: Intel Core i7-920 (2.66GHz)
* Mainboard: Gigabyte GA-EX58-UD3R (iX58 chipset)
* System memory: 3x1GB Samsung (PC3-10666, 1333MHz, CL9)
* Hard disk drive: 1000GB Seagate Barracuda 7200.11 ST31000333AS
* Graphics card: PCI-E 1792MB ASUS ENGTX295/2DI
* Optical drive: DVD±RW Optiarc AD-7201S
* System case: IN-WIN IW-J614TA F430 (550W)

I installed Microsoft Windows Vista Home Premium SP1 (32-bit) and necessary drivers on the PC.

Interesting

 

[froot]

You should remember that ie a 500W PSU cannot supply a constant 500W- the average PSU has an efficiency rating of 75% and it goes up to about 85/90% as you get to your high-end PSUs. It's also only for peaks- it's average sustainable power would only be about 400-450W.

 

[SanchoP]

And if it isn't a reputable brand they will claim a wattage when running at like 20 degrees, when it will actually run hotter and hence less efficiently. The other thing is that the output will decrease as the years go by. But the point is definitely right; people love recommending gigawatt PSUs when really a 500 - 600W unit should be fine for almost every use. Just make sure you get a reputable brand like Antec.

 

[chickenbeef]

I ran my Q6600 @ 3.6GHZ stable with 2x2gb ram, 2x dvd writers, a 500Gb hdd, 5x 120mm fans, 2x 8cm fans and a XFX 7900GT extreme all on a 250W Aopen psu, so i guess power requirements are a bit overrated. . .

this was over a 3 week period btw till i got a 585W psu

 

[Zenbaas]

You should remember that ie a 500W PSU cannot supply a constant 500W- the average PSU has an efficiency rating of 75% and it goes up to about 85/90% as you get to your high-end PSUs. It's also only for peaks- it's average sustainable power would only be about 400-450W.

True, but some of the more reputable brands will also almost "under rate" their PSU's where a 750W psu is able to always supply eg. 750W but has the ability to deliver 800+ W under load.

I ran my Q6600 @ 3.6GHZ stable with 2x2gb ram, 2x dvd writers, a 500Gb hdd, 5x 120mm fans, 2x 8cm fans and a XFX 7900GT extreme all on a 250W Aopen psu, so i guess power requirements are a bit overrated. . .

this was over a 3 week period btw till i got a 585W psu

Hell that is rather impressive actually!

 

[froot]

True, but some of the more reputable brands will also almost "under rate" their PSU's where a 750W psu is able to always supply eg. 750W but has the ability to deliver 800+ W under load.

True, I suppose, but not quite, according to the manufacturer descriptions and technical specifications.

 

[d0b33]

I can see my watts being used with a power meter and my system on full load won't peak over 280W, I'm running a 460W zalman and specs are in my sig.

so yeah watts are overated.

 

[froot]

I can see my watts being used with a power meter and my system on full load won't peak over 280W, I'm running a 460W zalman and specs are in my sig.

so yeah watts are overated.

I concur. I have an e8400,a 9800GT and a few hard drives and I'm sitting with a 360W PSU.....

 

[Zenbaas]

Power Supply Myths Exposed!

Pretty much what we have been saying but interesting nonetheless.