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Is this enough PSU for 8800 GTS?

Last response: in Graphics & Displays
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April 5, 2008 6:29:55 PM

As topic says I have this PSU..

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I can't figure out this +12v rail@26 blah blah stuff so please help me out.

Here is the card I want it to run.. Can my PSU handle it?

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

More about : psu 8800 gts

a b U Graphics card
April 5, 2008 6:50:45 PM

It goes like this. Each voltage has so many amps assigned/available to it. Theres the 3.3, the 5 and the 12 volt. Lets stick with the 12 volt, as thats what your gpu uses. If you have 26 amps on your 12 volt rail/s , all this means is that you have 26 Amps x 12 volt = 292 watts for the 12 volt rail. Amps x Volts = watts. Since gpus are listed in watts, thats how you break it down. The psu you linked to is only showing 14 and 15 amps on the 2 twelve volt rails. Thats not enough.
a b U Graphics card
April 5, 2008 6:57:30 PM

Now just cause it says 14 on one rail and 15 on the other doesnt mean it just adds together to be 29 amps. Thats the max amperage for each rail. On your selected psu it shows the 3.3 volt as having 30 amps. OK, 3.3 x 30 = 100 watts. On the 5 volt it shows 24 amps, so thats 120 watts or 5 x 24 = 120. Now, add the 100+120 plus the 292 watts from the 12 volt and you have? 512 watts total. But 14 amps and 15 amps isnt strong enough for your gpu. youll need something like 20 amps per 12 volt rail for that gpu
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April 5, 2008 7:15:39 PM

Ah ok, I think I get it now. :D 

Thnx for the info

Ok, well for my new system I was really looking forward to buying..

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

But, it looks like it doesn't even have the recommended amps on a 12v rail... Says it has 3 but each has 18A or so. This is a very popular PSU though.. obviously people are running 8800 series with this PSU. So where does the line get drawn? Nvidia I think recommends 12v @26A rail but this PSU is clearly under that mark for the rail individually. Now im confused again. ;x

Is Nvidia recommending a TOTAL of 26A through all the 12v rails? If thats the case then my current PSU is indeed enough. right?
a c 263 U Graphics card
April 5, 2008 7:22:43 PM

EVGA will suggest that your psu have 26a on the combined 12v rails to run the 8800GTS. This is obviously a generic recommendation, because it does not say what else might need the power in your machine. You have 29a(14+15) I think you are borderline. I think the vga card will actually use about 8amps, I think I read somewhere that it draws 92w. I suspect that that number is correct. A pci=e slot can deliver up to 75 watts, and the 8800gts needs a single pci-e connector that can deliver an additional 75w. That means that the card can draw on it's own between 75w and 150w, or between 6.25 and 13amps.

However, since you already have the psu, and it is a good brand, I would try it. At low loads, it should work ok. At maximum vga activity look for display artifacts or other types of flaky operation. In this case, I do not think you would harm anything by trying it out.

---good luck---
a b U Graphics card
April 5, 2008 7:39:19 PM

You don't have to find a PSU capable of 26A on a single rail (even 1000W PSU don't have that), you have to know the total amperage of the +12V circuit. On Thermaltake's website (here) they state the W0093RU as having 29A on the +12V so you might actually have what it takes unless they did a "marketting addition" of the 14+15 rails. If you can, call them and simply ask.

My 520HX has 3 18A rails, but on the website they say they support a combined 40A so I have no problem with the exact card you are looking at.
a b U Graphics card
April 5, 2008 7:46:58 PM

dostanio said:
hey jaydeejohn, so you cant add the 12v's to give u a total Amps?

I was trying to bid for this PSU, will it work for a 8800GTS 512, URGENT HELP NEEDED!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=15...
No you can't, but it doesn't mean you have to find a single 26A rail; just take a quick look on newegg and I bet you will have a hard time finding a PSU that would matches this criteria. You have to look at the total wattage or amperage of the +12V circuit. In the eBay auction, you will find under "Output Load Regulation" that for the 12V rail, you can go up to 30A (the 20A + 18A > 30A so no you couldn't just add them). If you can only get the wattage as a total for the 12V, divide by 12 and you get amperage ;) .
a b U Graphics card
April 5, 2008 8:00:53 PM

While true you can't just add the two rails, and that PSU doesn't specify the max combined, and 14A + 15A rails are wimpy for a 500W...... this chart does mention 29 amps for that PSU. http://forums.guru3d.com/showthread.php?t=205763

I wouldn't buy that PSU, but also think given fairly accurate 12v listings in that link, that it may be possible to run a G92 on that PSU.
April 5, 2008 8:03:33 PM

I have another question as well...

ATM I have a single-core AMD fx-55 CPU @2.6 ghz. 2 gig of RAM..

I was thinking my CPU might bottleneck a 8800 GTS (g92). I'm gunna be upgrading my whole system eventually but figured I'd get the video card in the meantime. Will I get full performance out of the card or is it going to be held back by my out of date CPU? and by how much you think?
a b U Graphics card
April 5, 2008 8:09:13 PM

Totally depends on the game. Games like Crysis and Supreme Commander don't do well on a single core CPU. You definately won't get the maximum potential in many new games, but in others your may find you take advantage of a G92. You'll often have to run a high res or enable fsaa though to make that card worth it over a 9600GT paired with single core CPU. But it will work for sure. If an upgrade wasn't in the near future I'd say grab a cheap 8800GS or 9600GT instead. Even then expect lower minimum fps and some laggy spots during heavy npc areas or physics effects.


BTW, I have an 8800GTS 320MB and an FX-55 that served me well until I bought Crysis. Still was playable in that game, but I had built so many better machines for other people it was time for an upgrade for me.
a b U Graphics card
April 5, 2008 8:15:34 PM

The usual answer to that is: "it depends on the game". It will hold you back A LOT in Supreme Commander (even a dual-core is a "hold-back" for that game :p ). As for other games I wouldn't know. My suggestion if for you to wait because by the time you buy the system and be able to truly enjoy it, its price will have dropped by probably 50$ unless your upgrade is planned with the next 1-2 months.

If you feel the need to start buying stuff for your next build, start by components that don't depreciate as much like a new LCD screen (I equipped my old Athlon XP 3200+ with a new 226BW about 2-3 months before upgrading and the prices still haven't dropped), a tower (much less fun, but cool non the less).
April 5, 2008 8:17:24 PM

To OP ..well there WILL be a performance increase when you install your new GPU, but you wont be very happy with it...its much better if you upgrade your CPU along with the GPU.

When are you buying the rest of your rig btw? And which PSU are you getting finally? :) 
April 5, 2008 8:35:41 PM

mihirkula said:
To OP ..well there WILL be a performance increase when you install your new GPU, but you wont be very happy with it...its much better if you upgrade your CPU along with the GPU.

When are you buying the rest of your rig btw? And which PSU are you getting finally? :) 


I'll be buying the rest of my rig at the very latest end of May. I have a pretty good reason to buy the video card early to hold me over. (Got accepted into a beta for the game I'm planning on upgrading for when its released) So you see my reasoning for it. I'm currently on a 7900GT and it's honestly not enjoyable playing the game with this card, the card has lasted my FOREVER.. But, its finally clearly out dated with this game.

As for the PSU, I'd really love to have a modular unit so the Corsair HX620 is still looking very appealing.. plus it's at a good price on.. http://www.buy.com/prod/corsair-620w-sli-certified-modu...

I've read this PSU is very reliable and can easily handle what I'm interested in upgrading to.

If anyone has a better suggestion please share. :D 
April 5, 2008 8:37:08 PM

Zenthar said:
No you can't, but it doesn't mean you have to find a single 26A rail; just take a quick look on newegg and I bet you will have a hard time finding a PSU that would matches this criteria. You have to look at the total wattage or amperage of the +12V circuit. In the eBay auction, you will find under "Output Load Regulation" that for the 12V rail, you can go up to 30A (the 20A + 18A > 30A so no you couldn't just add them). If you can only get the wattage as a total for the 12V, divide by 12 and you get amperage ;) .


thanks for that:) 

so would i be able to use that PSU for my 8800GTS 512? Thanks agian
a b U Graphics card
April 5, 2008 8:46:34 PM

edit: Sorry Dostonio. I thought you were refering to the power supply in the OP. That one in your link with 30 amps combined would be fine for a G92 GTS.

We don't know as your power supply label is missing the needed info to give you a definate answer. If it is 29 amps like the guru3d thread suggests you may be fine. But typically a PSU with a 15 and 14 amp 12v would have a lower combined max than 29 amps and probably not be enough. If you decide to do it, I would suggest budgeting in the possiblity of needing a new PSU just in case. If you can't afford or are unwilling to buy a new PSU, than you may want to buy the card at a local shop that offers full money back if it doesn't work for you. (BestBuy for example) That may be too expensive, so think about the risk.
April 5, 2008 8:55:20 PM

phuzed said:


As for the PSU, I'd really love to have a modular unit so the Corsair HX620 is still looking very appealing.. plus it's at a good price on.. http://www.buy.com/prod/corsair-620w-sli-certified-modu...

I've read this PSU is very reliable and can easily handle what I'm interested in upgrading to.

If anyone has a better suggestion please share. :D 


The Corsair 550VX has enough firepower... its avail for $55 at buy.com. Thats half the price of the 620, with a heck of a lot of amps on +12v rail (41 at that!)
April 5, 2008 8:57:08 PM

The 550VX is not modular, go for the 520HX
a b U Graphics card
April 5, 2008 9:42:43 PM

dostanio said:
The 550VX is not modular, go for the 520HX
I have it and I love it so +1. Go for the 620HX only if you feel you need lots of headroom.
April 5, 2008 9:44:06 PM

Zenthar said:
I have it and I love it so +1. Go for the 620HX only if you feel you need lots of headroom.


The 550 or 520?

They are both good, but the guy said he liked a modular.
a b U Graphics card
April 5, 2008 9:46:55 PM

Oops, +1 for the 520HX.
a c 230 U Graphics card
April 5, 2008 10:30:18 PM

http://www.nvidia.com/object/geforce_8800gt_faq.html

Quote:
Q: What are the recommended power supply requirements for both the GeForce 8800 GT in single and multi-GPU configurations?

A: GeForce 8800 GT graphics cards require a minimum 400 W or greater system power supply (with 12V current rating of 26 A) for single GPU operation. Please refer to www.SLIZone.com for a list of recommended SLI certified power supplies for multi-GPU configurations.
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