PSU calculator correct?

[drunknmunkys]

using this calculator: http://extreme.outervision.com/PSUEngine

I'm inputting:

-1 CPU
-AMD 720 OC'ed
-2 sticks DDR2 SDRAM
-Radeon HD 4890
-Crossfire
-1 IDE 5400rpm drive
-4 regular SATA 7200rpm drives
-1 DVD-ROM drive
-1 DVD-RW/DVD+RW Drive
-3 120mm LED fans
-1 250mm LED fan
---------------------------------------------

509W

That seems rather...low

 

[GhislainG]

That seems correct to me, but you should buy a more powerful PSU if you don't want to run it at 90% load. A 700W should meet your requirements.

 

[dirtmountain]

Here's a great article about power consumption drunk, well worth a read.
http://www.xbitlabs.com/articles/coolers/display/system-wattage.html

 

[Mousemonkey]

Here's a great article about power consumption drunk, well worth a read.
http://www.xbitlabs.com/articles/coolers/display/system-wattage.html

Good article, still not going to steer forum fanatics away from recommending PSU's with huge numbers for small rigs though, the 'bigger is better' mantra is too heavily ingrained in the forum collective, efficiency does even get a look in.

 

[drunknmunkys]

I've got a 750W PSU, I just wanted to double check and make sure I could xfire 4890's when I decide to get a 2nd one. That for the input and the article.

 

[drunknmunkys]

I've got a 750W PSU, I just wanted to double check and make sure I could xfire 4890's when I decide to get a 2nd one. That for the input and the article.

 

[jasmithvr6]

I just built a new box with a Core i7 860, Asus P7P55D EVO MB, 3 WD Blacks, 2 GTX 275's, 4 sticks of Mushkin DDR3, 2 DVD-RW's and 7 case fans. Before buying a Corsair 750W psu, I researced a bunch of different psu calculators...most of which recommended 1000W psu's. I ran the numbers on extreme.outervision.com and came up with a measely 504 watts of usage. I decided to go with the smaller unit and now I find myself trying to diagnose random reboots and instability issues. I'm going to unplug the 2nd GTX and see if that helps. Point being, if it ends up being a lack of juice from the psu I'm not going to be a happy camper. More importantly, if that's the case someone ought to put the kabash on the extreme.outervision.com website as it is understating power requirements and wasting a lot of peoples money.

 

[WR2]

I ran the numbers on extreme.outervision.com and came up with a measely 504 watts of usage.

That PSU calculator suggests a PSU rating - not the actual DC consumption of your system.

Besides un-plugging the 2nd GPU try stability testing with just 2 sticks of RAM.

 

[jasmithvr6]

That PSU calculator suggests a PSU rating - not the actual DC consumption of your system.

Not sure I follow the difference, although I'm far from an electrician to understand. If the extreme.outervision.com site suggests PSU ratings, shouldn't those ratings mirror (or at least come reasonable close) to any other PSU calculator?

Besides un-plugging the 2nd GPU try stability testing with just 2 sticks of RAM.

Pulled the 2nd GPU and still had stability issues caused by memory. Fixed the memory problems and seems to be stable. Now it's time to add the 2nd GPU back into the mix and see if the psu can handle it.

 

[WR2]

@ OP
TechPowerUp tested 4890 crossfire on an overclocked system. It's a little bit of 'apples to oranges' but should be close enough to be useful to you.

We can find reviews that say the PSU used in that test runs about 85% efficient in the range of the test.
420W measured at the wall socket means the whole system is drawing about ~357watts DC power from the PSU.
And PSUs ratings are in DC output.
I know there aren't many that will be convinced their 'monster rig' is fairly 'dainty' when it comes to sipping electricity.

 

[WR2]

Not sure I follow the difference, although I'm far from an electrician to understand. If the extreme.outervision.com site suggests PSU ratings, shouldn't those ratings mirror (or at least come reasonable close) to any other PSU calculator?

Thats OK, you got the THG forum guys.

Ideally, you'd want the PSU calculators to mirror 'reality' instead of each other. Finding a SLI review and checking the actual power consumption of a test system and comparing that to a PSU calculator is a smart move IMO.
Just be aware that the wall socket draw (AC) shown in the reviews isn't the same as the DC draw from the PSU to the system parts. If you know the efficiency of the PSU you can estimate the DC usage for those test conditions.