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550w PSU enough for 2x8800gt in SLI?

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November 20, 2007 2:17:26 AM

I'm running 6 hdds internally (PATA + SATA), an Athlon X2 4800+ (s939), 4gb RAM, creative Audigy 2 zs sound blaster, 2x optical drives. I've got a good ANTEC 550w NeoPower/TruePower power supply.

Will I be able to run 2x8800gts in SLI mode for Crysis (so under high load)? Will the system hold up? I borrowed an 8800gtx last year and it ran just fine, but I don't know how the power consumption will be between 1x8800gtx and 2x8800gt cards... think I can pull it off?

More about : 550w psu 2x8800gt sli

November 20, 2007 2:21:19 AM

oh and nothing is overclocked.
November 20, 2007 2:50:36 AM

I wouldn't. You probably want 650 at least just to be safe. The only reason I say that is because of the massive amount of HDs plus the extra optical.
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November 20, 2007 2:51:00 AM

Couldn't hurt to try though.
November 20, 2007 3:36:45 AM

Your Antec may fire it up but could cause freezes, bsod's and all sorts of problems. I would get a 700w+.
November 20, 2007 3:39:43 AM

http://www.extreme.outervision.com/psucalculatorlite.js...

use this to calculate your power needs. Corsair's hx520 or hx620 have great reviews and have modular cables.



EDIT-From just what u listed, I calculated 509 watts needed using above link. But you may want to input ALL items that draw power. Looks like a 600W may be in order, as these programs recommend some leeway. Good luck.

November 20, 2007 5:17:27 AM

thanks guys. OK SO... I used that calculator thing, but everything I had and even added a PCI card and 2 USB devices that I don't have for some "leeway" plus put all system load at 100%... which came to 638 watts...

BUT, when I dropped it down to only 2 HDDs and left everything at 100% load and had more components then I had, it says 538watts... and if I drop it to 1 HDD and get rid of my optical drives and have only 1 USB device, say a gamepad, it drops it to 447watts!

So here's my question:

No way I am getting a new PSU right now, BUT, I really want to get 2x8800gts in SLI. Do you think if when I play games (which really isn't all that often, but I will be having a marathon with all these new games coming out) if I just UNPLUG ALL MY *EXTRA* optical & HDD drives while I play (I use all that for video editing, no need for them to be plugged in while gaming) that I should be safe then? Could that be a workable solution?

November 20, 2007 6:02:53 PM

NO way man. I would go at least with a 700w PSU, 550.. not a chance.
November 20, 2007 8:27:59 PM

the amount of HDD's are going to kill the thing on bootup, get something more powerful, 620-50+ wattage range.
November 20, 2007 9:10:42 PM

Man that would be cutting it close. You should probably skip out on SLI until you can afford a slightly better PSU.
November 20, 2007 10:23:22 PM

OK - so no go with everything plugged in. But what about how I mentioned unplugging what I am not using?

If I...

- unplug all HDDs (5x), except my main boot drive / game install drive
- unplug all optical drives (2x)

Should that be ok? I thought I read somewhere that in SLI, the 8800gt needed only 450watts... and that power chart shows if I unplug those components that at 100% load I'll be drawing less than 500watts.

BUT - am I missing something? Will that still not work? If not, why not?

Thanks so much for the input.
a b U Graphics card
November 21, 2007 10:13:57 AM

Pintail said:
I already gave him a psu calc link, he's used it. http://www.extreme.outervision.com/psucalculatorlite.js...
Looks much the same as yours. Wonder if results will be?


I realize you had already given a link to one psu calculator, this one provide's a little more info.
Entering dannyaa's specs, it gave me a reccomendation of 510 watts, not to far off the 509 that you got from the EPS calculator.
November 21, 2007 10:38:58 AM

Hammer!!!

Good to go, run the 2x8800gts in SLIs.

And love every minute of it!


November 21, 2007 12:40:28 PM

NO WAY dude!

MY secondary system has 4x raptors150s and 2x500gb drives with 2x7900gtx 1x optical drive.

PSU calc said 614 watts ...... The 650 PSU I had in there poped like a little $%@#^ it lasted maybe 6 months. You would be surprised how many watts each HDD uses on spinup/startup. you can find out on the HDD manufacturers website. (well atleast WD has all that info on their site ... I only buy WD)

my new rig has 4x raptors 5x1TB drives raid5 1xblur-ray/hd-dvd burner 1x dvd-dl burner and 2x 8800gt and im running the Enermax Galaxy DX10 1kw

One thing I've learned over the years if you are building a out of the norm rig dont skimp on the PSU otherwise you might end up with more than just a dead PSU.
November 21, 2007 1:22:55 PM

Buy a cheap device (about $15) called a Kill-A-Watt and see how much your computer pulls at load. It can measure the wattage. Now, this is the wattage pulled from the wall, not the wattage the power supply is giving to the computer (which is always less than the power that the power supply draws from the wall). See how much power you pull. I currently have a e6600 overclocked to 375*9=3.375GHz, 8800GTX, 3 SATA HDD, 2 Optical drives, the nautilus 500 watercooler (runs off the power supply power), X-Fi fata1ity, 2GB of ram, and only pull about 330watts from the wall when loaded during gameplay. So if you consider (for calculations only) my power supply to be 90% efficient (which is way high), the power supply is (at max) only providing ~300 watts of power. I think it's a little over 80% efficient, so it's providing about 270 watts. So my 500watt is perfectly fine.
a b U Graphics card
November 21, 2007 2:00:53 PM

gwolfman said:
Buy a cheap device (about $15) called a Kill-A-Watt and see how much your computer pulls at load. It can measure the wattage. Now, this is the wattage pulled from the wall, not the wattage the power supply is giving to the computer (which is always less than the power that the power supply draws from the wall). See how much power you pull. I currently have a e6600 overclocked to 375*9=3.375GHz, 8800GTX, 3 SATA HDD, 2 Optical drives, the nautilus 500 watercooler (runs off the power supply power), X-Fi fata1ity, 2GB of ram, and only pull about 330watts from the wall when loaded during gameplay. So if you consider (for calculations only) my power supply to be 90% efficient (which is way high), the power supply is (at max) only providing ~300 watts of power. I think it's a little over 80% efficient, so it's providing about 270 watts. So my 500watt is perfectly fine.

E6600 @ 3.0 | 4 gigs of ram
8800 GTS @ 647/1512/951
3 SATA hard drives
single DVD R/W
SB Audigy 2ZS
7 LED and 2 standard fans
From the wall: 321 watts gaming / 215 watts idle / 80% efficient psu = 257w gaming / 172w idle
November 21, 2007 2:29:22 PM

gwolfman said:
...e6600 overclocked to 375*9=3.375GHz, 8800GTX, 3 SATA HDD, 2 Optical drives, the nautilus 500 watercooler (runs off the power supply power), X-Fi fata1ity, 2GB of ram, ... 330watts from the wall when loaded during gameplay...I think it's a little over 80% efficient, so it's providing about 270 watts...


delluser1 said:
E6600 @ 3.0 | 4 gigs of ram
8800 GTS @ 647/1512/951
3 SATA hard drives
single DVD R/W
SB Audigy 2ZS
7 LED and 2 standard fans
From the wall: 321 watts gaming / 215 watts idle / 80% efficient psu = 257w gaming / 172w idle

From our two scenarios, you'd probably be ok. And I don't think you're overclocking, so that'll help lower your power requirements. I can't imagine another 220+ watts just on another video card (to your benefit, 8800GT uses less power than a GTX) and a few more HDDs (~5-7 watts a piece).


The setup above (from link provided above) shows only 327 watts used with 8800GT SLI, Core 2 Extreme X6800, NVIDIA 680i SLI, 4x1GB Corsair XMS2 PC2-6400 4-4-4-12, and one HDD. I think power supply wattage if over-hyped.

*updated picture to show load*
November 21, 2007 2:40:07 PM

What about under load, that chart is idle.
November 21, 2007 3:01:36 PM

Ok I've asked this a few times so...

*** WHAT IF I UNPLUG ALL MY EXTRA HDDS AND OPTICAL DRIVES ***

(I explained this in my above posts, see those for details)
a c 143 U Graphics card
November 21, 2007 3:37:53 PM

You're actually going to do that every time? You'll ruin the connectors eventually through all this wear and tear. Or you'll get an electric shock.
November 21, 2007 3:49:06 PM

dannyaa said:
Ok I've asked this a few times so...

*** WHAT IF I UNPLUG ALL MY EXTRA HDDS AND OPTICAL DRIVES ***

(I explained this in my above posts, see those for details)

I updated the picture above to show load. I don't think you have to unplug stuff, you should be ok. If you start running into problems, then unplug stuff, but I personally don't think you have to.
November 21, 2007 3:52:32 PM

dannyaa said:
Ok I've asked this a few times so...

*** WHAT IF I UNPLUG ALL MY EXTRA HDDS AND OPTICAL DRIVES ***

(I explained this in my above posts, see those for details)

*** YES IF YOU UNPLUG ALL YOUR EXTRA HDDS AND OPTICAL DRIVES YOU WILL BE FINE *** :D 

Since you're not overclocking I'd say you'd be fine even with the HDDs and other drives. It would just be close, and with PSUs it's usually not a good idea to cut it close. I'm not saying go out and buy a 1000 watter, but something in the 600-750W range would serve you better. Here's a few examples (notice how they all have a single 12V rail)

SILVERSTONE OP650
CORSAIR CMPSU-650TX
And the big daddy of them all: PC Power & Cooling Silencer 750 Quad
November 21, 2007 3:58:43 PM

I have a question for you, when you are not gaming are you going to remove one of the video cards?
It seems that you have a very powerful system and to go along with that you require the power to run it.
PSUs are the only area you should never skimp on. I would say that you should get the best PSU for your system.
I would recommend this PCPower PSU.

http://www.pcpower.com/products/viewproduct.php?show=S7...

Newegg had this with a good discount last week.

http://preview.tinyurl.com/2w34df
You need to use this code to get the added discount: EMC1115CASE01

A personal word of caution, I have in the past killed a system buy using an underpowered PSU.
a b U Graphics card
November 21, 2007 4:15:46 PM

dannyaa said:
Ok I've asked this a few times so...

*** WHAT IF I UNPLUG ALL MY EXTRA HDDS AND OPTICAL DRIVES ***

(I explained this in my above posts, see those for details)


I think you'll be fine, you have a good quality 550 watt power supply that you're going to draw around 360 watts from.
November 21, 2007 4:18:50 PM

ooph thats gonna be cuttin it close, get a new PSU and avoid the hassle.
November 21, 2007 4:33:45 PM

At least let us know if it fries.
a b U Graphics card
November 21, 2007 4:39:54 PM

@OP. Trust the people who says you to go with a 700W PSU. I have had bad experience with running SLI setups with low powered PSU's.
a b U Graphics card
November 21, 2007 4:40:48 PM

Oh, and also look in to a dedicated PSU for graphics only. Most of the time it is cheaper and works better.
November 21, 2007 7:00:37 PM

what are your 12v rail(s) amp ratings?
November 23, 2007 7:45:56 AM

gwolfman - my psu specs are here:

http://www.newegg.com/Product/Prod [...] 6817103941

I don't switch between gameplaying and video editing too much... I really only play games one main time a year, Holidays. I think I'll just unplug all my extra video HDDs/opticals and use the 8800gt. When I get back to video work in Jan, I'll unplug the 8800gt and replug in my HDDs.

Those PSU charts say if I do that, I'll have PLENTY of headroom, even at 100% load. If I were to play games more or leave everything plugged in, I'd just get a new PSU but I'm not going to use that setup enough to justify spending even more.
November 23, 2007 10:33:02 AM

Your PSU is probably enough for 2x8800GT
But I think that your CPU can't even keep up with one GT, unless you play at very high resolutions. For SLI GT's I would recommend at least 3GHz C2D. You may even have less power consumption and this would be even better for your current PSU.
November 23, 2007 1:21:55 PM

dannyaa said:
gwolfman - my psu specs are here:

http://www.newegg.com/Product/Prod [...] 6817103941

I don't switch between gameplaying and video editing too much... I really only play games one main time a year, Holidays. I think I'll just unplug all my extra video HDDs/opticals and use the 8800gt. When I get back to video work in Jan, I'll unplug the 8800gt and replug in my HDDs.

Those PSU charts say if I do that, I'll have PLENTY of headroom, even at 100% load. If I were to play games more or leave everything plugged in, I'd just get a new PSU but I'm not going to use that setup enough to justify spending even more.

Looks like you're all set then. Enjoy the setup!
December 11, 2007 3:58:03 AM

Just an update for those curious:

I have been using 2x8800gt SLI on my 550w Antec NeoPower PSU, with my x2 4800+ (system specs in sig). I unplugged a few extra items, but left two SATA hdds and an optical drive plugged in.

No problems, crashes, freezing or anything. Beat CoD4, Half-Life 2 Episode 2, been playing Timeshift, TF2, Portal, BioShock, and Crysis all with no problems.

December 11, 2007 4:23:44 AM

Good to hear a follow up..

Try to add one hard drive at a time :p 
!