How many amps for an 8800gt?

[Burninator]

How many amps does an 8800gt need? I'm going to have 3 (well, 2 8800gt's, one 9800gt) in a folding rig/server of mine, and want to know how many amps each would need.

thanks in advance

:up:

[Frag Maniac]

For one 8800GT, 26a combined 12v rail. Your TX850 has 70a combined 12v. Here's a handy guide for combined 12v amperage on many PSU in case you need more power. http://forums.guru3d.com/showthread.php?t=205763

[zanzabar]

i would guess that the 65nm ones would need 10-12

[Burninator]

hm... well my 500W antec says it has 3 12v rails at 17amp each... that enough? lol. doesnt sound like a good idea... 3 8800gt's on a 500w...

[zanzabar]

that would be enough for the cards but then u wouldent have anything left for the cpu.

i would suggest picking up a cheap corsair 750 or 850

[Frag Maniac]

hm... well my 500W antec says it has 3 12v rails at 17amp each... that enough? lol. doesnt sound like a good idea... 3 8800gt's on a 500w...Ah ha, my mistake, I was going by what your sig says for your main rig. Personally, I would use a more powerful unit than that 500W Antec you have, which at best has 38a combined on the 12v rails from what I've read. The TX850 would probably easily handle it, mainly because in SLI one GPU always works harder than the other(s).

On what zan said, I already knew the lower die size 8800s were the ones that 26a was recommended for, but found some info last night indicating the 8800GT does too. It's never a good idea to push your luck with PSU amperage for GPUs.

There were less capable GPUs made before the 8800s that actually required MORE amperage (like my X1950Pro, which requires 30a). When they got to 26a for that level of GPU, it was considered more efficient. Let me make one thing clear though. When rec amperage is listed, it is ALWAYS a rating for the max (peak) load you can possibly put on the GPU.

You may never actually reach that peak, esp in normal use. It could take something like an extended synthetic bench. Reason they're reced that way though is you can do serious damage if you ever DO reach the point where the GPU is trying to draw more amperage than is available.

If you want safe GPU amperage recs, check with EVGA. They're the only ones I know of responsibly mentioning both PSU wattage AND amperage. The 9800GT is basically a regbadged 8800GT as far as raw power. Only minor features were added. EVGA verifies that what I read about 26a rec is the correct safe amount.

GeForce 9800 GT PART NUMBER: 512-P3-N973-TR

Requirements
Minimum of a 400 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 26 Amps.)

Source
http://www.evga.com/products/moreInfo.asp?pn=512-P3-N973-TR&family=GeForce%209%20Series%20Family

HOWEVER, after some more checking on SLI Zone and Antec's specs on Nvidia's lowest wattage PSU listed as being certified for tri SLI with 3 9800GTXs, it would appear there's an Antec True Power New 550, with what looks to be 45a on the 12v rails. So, from that we can pretty much ascertain that 45a combined is an adequate amount for tri SLI 8800GT, as long as the PSU is a stable one like those on Nvidia's list.

http://img38.imageshack.us/img38/1742/tri9800gtxpsus.jpg

The continuous maximum total output power shall not exceed 550W.
+12V1, +12V2 , +12V3 and +12V4 DC maximum output power shall not exceed 540W (45A).

Sources
http://www.slizone.com/object/slizone_build_psu.html

http://www.antec.com/pdf/manuals/TP-550_Manual_EN.pdf

That's a $100 PSU, pretty hefty price for the wattage. http://www.newegg.com/Product/Product.aspx?Item=N82E16817371020&Tpk=Antec%20True%20Power%20New%20550

Make no mistake about it though, it makes a BIG difference how they're designed. Well made ones can push continuous high wattage/amperage loads, others cannot. That's why Antec calls those their "CP", or Continuous Power series. Sometimes even ones rated at lower wattage can outdo ones rated higher when under severe load, so be careful what you look for. It could be a mistake to look for the cheapest one with 45a combined. However if it's one that's highly rated by a site like Jonny Guru, whom specializes in PSU testing, it would be a fairly safe bet.

[Burninator]

Well the cards will be 100% load 24/7 for folding... so I don't REALLY want to take chances... but i dont want to spend lots of money either :p: I have another one lying around (currently in my mom's comp):
http://www.newegg.com/Product/Product.aspx?Item=N82E16817103941&Tpk=neopower%20550w

it's a little old.. i know i SHOULD just get a new PSU with like >650W, but i already need to buy a new mobo... lol i need more moneyz

edit: thanks for the links btw :up: great info

[Frag Maniac]

No problem, lots of people forget about SLI Zone and/or don't know about that or EVGa's amp recs. One thing I'm sure you do know though is that having a secondary PC rig dedicated to tri SLI folding is a luxury, and even though it's a potential life saving one for those whom need cures, it DOES take a certain expense to setup right. Kudos though, and maybe someone can create a program to help figure out the population problem once all diseases are cured. ;)

That being said, I've been reading about natural healing remedies lately, namely those derived from cacti, and I really think that's a better way to go than trying to reinvent the human body through genetic research and engineering. I've known for some time that certain succulents are powerful, but they're now becoming mainstream. There are fruits from plants such as the Nopal cactus that are known to help animals and humans native to their areas live very long healthy lives.

One of the biggest life lessons to learn is that the human body itself can heal itself from most problems if it's fed properly. It's all about preventative maintenance.

[zanzabar]

are u sure on sli zones rating for that psu it seams like an aged 550W and an i7 even on a strong 12V psu would be to much for it

[Frag Maniac]

Well one could always ask Nvidia if it's really been tested thoroughly for it, but I trust if they're going to add any PSU to those SLI scenario lists, you can be sure they have been, for gaming anyway. In his case if he's leaving it running doing folding though, I'd go a good 100 watts higher at least, even with a highly rated one that can push continuous power. Like I originally said, that TX850 in his sig is looking a lot more appropriate for such a task.

[Burninator]

I know the TX850 is more appropriate, but the nice stuff goes in my main machine :D folding rig gets the extras :)

Picked up a motherboard yesterday - just need the PSU now. Anything at or above something around a TX650 should do fine right?

[Frag Maniac]

Anything at or above something around a TX650 should do fine right?I would say so, as long as it can push continuous loads well like I said.

[Burninator]

I have one of these lined up (from someone here), it should do nicely no? :)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703029&nm_mc=OTC-Froogle&cm_mmc=OTC-Froogle-_-Power+Supplies-_-PC+Power+and+Cooling-_-17703029
:up:

[Frag Maniac]

Easily, a very good PSU with 60a on the 12v rail. It's a bit longer than a standard PSU though, so make sure your case has room for it.