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Power supply calc - somethings not right

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May 30, 2008 2:08:14 AM

with the extreme outervision calculator, i get a total of 308 watts usage for my system

but on http://www.evga.com/products/moreinfo.asp?pn=512-P3-N84... it states that my video card requires 400 watts itself!

my major parts are

evga 8800 gts 512mb
q6600 not overclocked (dont know which step)
nic card, sound card (2 pci slots)
three 120mm fans with led, one 200mm fan with led (antec 900)
and two sticks of gskill 2 gb memory

>.<
May 30, 2008 2:17:04 AM

that seems right. it only says its recommend 400watt not for itself (gpu) but entire system. im running a q6600 oc@ 3.0ghz and a oc 9800gx2 on a antec earthwatt 500.
May 30, 2008 3:38:04 AM

geesus invisik, i would think that would be a close call.

But your totally right, 400w rating on evga is total system power not just GPU.

Id suggest a Corsair450TX or 550TX they are fairly cheap and good PSU's
Related resources
a b ) Power supply
May 30, 2008 3:46:08 AM

The 8800GTS 512 uses 99w at peak power consumption
a b ) Power supply
May 30, 2008 3:53:18 AM

From Toms review of the 9800GTX Power Consumption And Temperature
Power Consumption
As usual, we measured the power supply's consumption for these cards (which means that the consumption of the entire configuration is measured). We also gauged the power-supply losses, which are approximately 18% in the range we're concerned with.



While it requires an additional six-pin power connector, the 9800 GTX' consumption is actually very close to that of the 8800 GTS 512 MB, which is not surprisingly. The figures were comparable in idle state and just slightly higher under load (running Test Drive Unlimited), as its specifications indicated. Officially, Nvidia specifies 156 W for the 9800 GTX as opposed to "< 150 W" for the 8800 GTS 512 MB, and our results confirmed that.

What that means is that a brand-name 350 W power-supply will be enough to feed a system based on this card. We should mention that despite the reduction in memory quantity and the change in engraving depth, the drop in power consumption compared to the previous generation is nothing to write home about - it works out to only 21 W once you correct for the power-supply losses. On the other hand, the performance/watt yield is obviously much higher (by 52%) compared to the Radeon HD 3870 X2, whose consumption we measured with Unreal Tournament III because it was just too underused with Test Drive Unlimited (We measured 235 W, which was actually less than the 8800 GT).
265watts at load for the total test system


a b ) Power supply
May 30, 2008 3:16:36 PM

dirtmountain said:
The 8800GTS 512 uses 99w at peak power consumption


That's assuming the 8800GTS 512MB is running at stock speed.

If it is factory OCed or OCed by the owner, then it will draw more power.

I would guess up to an additional 10w - 12w depending on how much of an OC.
a c 80 ) Power supply
May 30, 2008 3:50:13 PM

Hell for me the psu calc over estimates.

In my case it shows about 447(90% tdp & system load) and my system rarely pulls more then 330(i can get it up to about 370 with some real pushing) from the wall(so the DC load is a good 20% lower once you factor in the psu losses)

The system idles around 200 watts, 240-260 folding and 300-330(it varies from game to game) with games added.

Not saying to run out can get a 350 watt psu, but as long as its a good stable psu and sends enough of its power to the 12 volt lines you should be ok. There are many cheap 500 watt psu's out there with as much 12 volt power as a good 350. That may be another reason why EVGA over estimates, then even a cheap psu will run without issues as long as its that far over what is actually needed.


Also overclocking increases power use by allot. To take my Q6600 from 3.0 - 3.6 requires 100(give or take 10 watts) watts extra. Video cards are the same at a point during overclocking the power use jumps a fair bit.
a c 144 ) Power supply
May 30, 2008 4:09:40 PM

Based on jscasteel's mental PSU calculator:

evga 8800 gts 512mb - 100 - 120 watts if OC'd
q6600 not overclocked - 90 watts, 120 watts if OC'd
nic card, sound card (2 pci slots) -???
antec 900 case - fans on anything less than high - 12 watts
and two sticks of gskill 2 gb memory - 6 amps @3.3 volts = 20 watts
midrange motherboard like EP35-DS3P - 2 amps @12 volts = 24 watts
3 amps @5 volts = 15 watts
HD - 20 watts ea
DVD - 30 watts ea

I get about 330 watts, and I estimate I'm about 10% high because where I measured, I rounded amps upward. Where I estimated, I used high side estimates. Call that 10% Mr. Murphy's share.
May 30, 2008 4:17:01 PM

Best way to calculate is based on the actual components power usage. Look at the box.
Power supply calculators can only approximate. Outervision.com is said to be on the low side.
May 30, 2008 4:22:58 PM

OP- Do you now have a PSU and are trying to figure out if it puts out enough power, or are you trying to figure out what size of PSU to buy? All the discussion is nice, but unless we know what's behind the question, its hard to give a solid answer as to your needs.
a c 139 ) Power supply
May 30, 2008 5:19:19 PM

ispy said:
it states that my video card requires 400 watts itself!

It does not state your "video card requires 400 watts itself!"

It says:




a c 144 ) Power supply
May 31, 2008 12:11:12 PM

evongugg said:
Best way to calculate is based on the actual components power usage. Look at the box.
Power supply calculators can only approximate. Outervision.com is said to be on the low side.


Or measure.

"q6600 not overclocked - 90 watts, 120 watts if OC'd
and two sticks of gskill 2 gb memory - 6 amps @3.3 volts = 20 watts
midrange motherboard like EP35-DS3P - 2 amps @12 volts = 24 watts
3 amps @5 volts = 15 watts "

All based on measurements with a lab calibrated clamp-on ammeter. I was really surprised at how little power a motherboard usues by itself.
May 31, 2008 1:50:50 PM

I'm usually under the impression when you see what a site recommends, I think they are saying if you have a maximum setup, to where there's nothing left to hookup on the MB/PSU. :lol: . o O (but I've been wrong before)
a c 144 ) Power supply
June 1, 2008 4:55:48 PM

Grimmy,
Also related to computer requirements on game boxes:

"Minimum" = count on your fingers frame rates
"Recommended" = "Minimum"
June 1, 2008 5:38:01 PM

jsc said:
Grimmy,
Also related to computer requirements on game boxes:

"Minimum" = count on your fingers frame rates
"Recommended" = "Minimum"


Errr..

Recommended = Whatever they think

Minimum = Minimum

For example, right off my Oblivion Game box:

Recommended:

1GB RAM / 3Ghz P4 or Equiv CPU / ATI X800 - 6800 NV or higher

Minimum:

512mb RAM / 2ghz P4 or Equiv CPU / 128MB Direct3D compatible video card and DX9

Heh.. they don't say anything about PSU.. garsh darn it. :lol: 

But what I was saying in my above post, I just remember requirements stated of like NewEgg, to where it depends on how loaded your system is, when it comes down to the PSU. When you run 4-6 HD will cause more Power Draw, then a system with just 1 HD is what I'm saying.

Edit:

I think things got too complicated for sites on hardware, so they stopped putting them on their (NewEgg/ZipZoom/ect) spec's page when you look at their hardware.
!