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SLI 9800Gt Power Supply

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May 17, 2011 2:15:22 AM

Hey Guys, I have one quick question. I have already read over the forums to find an Anwser but, Some places say I can run SLI On my PSU and Some say I cant. I really need to be sure. I know that My PSU Is going to be pushed to the limit but I want to know If It can Run dual 9800Gt's

Specs:
Core i7 870
16GB's DDR3 Mushkin Silverline Ram
Gigabyte P55-Ud4P
OCZ ModXStreamPro 500watt
NZXT M59
One Gigabyte 9800GT Want to SLI

Okay So I know that My PSU Is 500Watts and It has Dual 18 Amp Rails which is around 36 Amps. My worries is that 36 Amps is not enough for SLI with 2 9800's. I have read many Forums including some on Toms Hardware but none give me a conclusive anwser. I found another 9800 for 45 Dollars Canadian and I really want to SLI My Rig. I just really want a conclusive anwser if my PSU Is able to handle Dual 9800's. No I will not be Oc'ing anything in my System. I do think that This OCZ ModXStreamPro Is pretty decent... Correct me if Im wrong. But Again I would like one conclusive answer as If this PSU Is able to SLI 2 9800s. I got One 6+2Pin and one 6Pin Leads coming out of the PSU. Thank you Guys Very much in Advance. ((Im not sure if I posted in the correct forum... If Im wrong, Please feel free to move this somewhere else.))

Yuvin Weerasinghe
a c 273 ) Power supply
May 17, 2011 2:43:59 AM

I would have to say no,i think you need more juice.
Most reviews i've read recommend a 450W psu for one card.
Have only found reviews of GX and GTX models = 450-550W psus recommended for single cards.
http://www.guru3d.com/article/geforce--9800-gtx-sli-rev...
I'm aware your model probably uses less power but i think it's safe to assume a 500W psu isn't going to cut it for two cards.
OCZ FATAL1TY Series 750W
http://www.directcanada.com/products/?sku=13220AC3281&v...

May 17, 2011 2:47:27 AM

Thanks for the Reply Davcon... I think it actually takes alot less power. I think the 9800 Maxes out at 114 Watts and the GTX Maxes out at like 143 Watts.. Any other Opinions... I only need to use this PSU for around 1 Month and Im switching it into an old PC and getting a new one for my self.
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a c 1103 ) Power supply
May 17, 2011 3:31:30 AM

A single reference clocked (i.e. 600 MHz core) GeForce 9800 GT graphics card has a Maximum Graphics Card Power of 105 Watts (8.75 Amps from the +12 Volt rails).

A minimum 400 Watt or greater system power supply with a minimum 12 Volt current rating of 26 Amps is recommended for a single card system.

For a two card system in 2-way SLI mode a minimum 500 Watt or greater system power supply with a minimum 12 Volt current rating of 35 Amps is recommended.

Your OCZ Mod XStream Pro OCZ500MXSP is actually able to produce its labelled 36 Amps on its two combined +12 Volt rails. Hardware Secrets was able to draw 40 Amps from the combined +12 Volt rails during its measured maximum power draw of 569.8 Watts from that PSU model.

It is theoretically possible to run your system with two cards in SLI. If you don't over clock the graphics cards you may just be able to get it running.

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a c 80 ) Power supply
May 17, 2011 3:57:35 AM
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http://www.motherboards.org/reviews/hardware/1821_2.htm...

With a TDP of 105W, two of these should be around 200W. Notice that these are 65nm versions, the 55nm should use a bit less. If you figure 200W for the cards, 100W (or more if you have a 125W, 140W, or OC'd CPU) for the CPU, and 50W or so for everthing else, you need around 350W on the 12V rail for this SLI setup.

Here is a review of your psu.

http://www.hardwaresecrets.com/article/OCZ-ModXStream-P...

They could pull a total of 35A or 420W off the 12V rail. In their test to pull more then the unit is rated for they got a total of 40A out of it before the units OCP would kick in. This is enough power to do what you want.

I'd like to point out that I wouldn't get a DX10 card at this time. The fastest card similar to your 9800GT power wise is the 5770. It has GTX260 like performance in the same power envelope as your 9800GT. Two of these in CF would perform much better. I know you're probably looking at total cost however and for the $50-$80 you're probably spending I doubt you'd get anywhere near the same level of performance.
May 17, 2011 8:10:58 PM

Hey Guys, Thank you alot for your responses. Now I will go out and Buy another 9800gt. And 4745454b I understand that the 5770 Is great with low power consumpsion, But right now, I got a deal on a used but still working 9800gt (I think it Was Asus) for only $40. I may choose to swtich to ATI's cards but right now, I want another 9800 for SLI. I am hoping to upgrade to one of Nvidias new 5 Series with an updated PSU. Anyways, Thank you All for your Replys. Admins may close this thread.
a c 80 ) Power supply
May 18, 2011 12:58:48 AM

I figured you were hoping to add in the second card for cheap. I just wanted to point out that a second card would basically give you a 9800GX2. Going from memory this should be something around a GTX260. Problem is the $100 5770 is also around the same performance level, gives you DX11, and uses the same amount of power as your current single card. Yes its more money, but getting the single card might make more sense. But I also understand that if you don't have $100, you don't have it. (sell your 9800GT for $40 and pony up the extra $20?)

Thread will get closed when you pick a best answer.
May 18, 2011 3:42:03 AM

Best answer selected by Yuvinmw.
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