Are two 18A 12V rails good enough for 8800gts (needs "26Amps")

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PETEKW

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My 8800GTS 320MB is arriving today - and I want to know what to expect in terms of power supplyiness. :p

The evga site says "Minimum of a 400 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 26 Amp Amps.)"

Is that for the card alone on one rail?!?! Somehow I doubt it.

I have a FSP 450PN. (http://www.fsp-group.com.tw/english/1_product/2_detail.asp?mainid=1&fid=123&proid=517)

It says it has 2 12V rails @18A. So, I have a combined 36 Amperes. Will this be OK for my new video card? :confused:

Thanks guys! :D
 
No. It just has it rated at a 26 amp power supply to be sure there are enough amps left over for the rest of the PC. I believe the 8800GTS uses around 10 - 15 amps.

Someone please correct me if I am wrong.
 
PETEKW said:
My 8800GTS 320MB is arriving today - and I want to know what to expect in terms of power supplyiness. :p

The evga site says "Minimum of a 400 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 26 Amp Amps.)"

Is that for the card alone on one rail?!?! Somehow I doubt it.

I have a FSP 450PN. (http://www.fsp-group.com.tw/english/1_product/2_detail.asp?mainid=1&fid=123&proid=517)

It says it has 2 12V rails @18A. So, I have a combined 36 Amperes. Will this be OK for my new video card? :confused:

Thanks guys! :D
Click to expand...

It should be enough. Your psu has 2 18a rails, but it is NOT 36a combined. You do not add them together. In your case, combined total is 360w = 30a. You have enough.

FireDemon said:
No. It just has it rated at a 26 amp power supply to be sure there are enough amps left over for the rest of the PC. I believe the 8800GTS uses around 10 - 15 amps.

Someone please correct me if I am wrong.
Click to expand...

Nope. The 8800GTS doesn't use 10-15a. They say 26a combined because of all the shitty generic psu's on the market that won't do what they are rated for. You could run an 8800gts on a quality 350~w psu with less than 26a. Not recommended though.
 
Hmmmm. I was only taking an educated guess since under full load (not even most games can get it towards this point) an 8800GTX uses almost 200 watts. I was estimating the GTS to only be a bit lower, so I estimated average load to be about 150 watts. so I thought it woule be 150/12 = amps.

How many amps would you say the GTS uses? GTX?
 
FireDemon said:
Hmmmm. I was only taking an educated guess since under full load (not even most games can get it towards this point) an 8800GTX uses almost 200 watts. I was estimating the GTS to only be a bit lower, so I estimated average load to be about 150 watts. so I thought it woule be 150/12 = amps.

How many amps would you say the GTS uses? GTX?
Click to expand...

The whole system takes 200 watts. Extreme power supply calculator says 145 watts for the GTX, and 123 for the GTS. I'd say that's an overestimation.
 
I have two 8800gtx in SLI and accroding to my UPS voltage mesurement in its software my system uses roughly 100 watts more when there is any kind of video card load. I would say then that a resonable estimate of actual wattage on the 8800gtx would be in the 100 watt range.Heck my whole system uses 500 watts max....
 
resolved. The 8800 comes with a 12v rail combiner. It's a simple hack so that I can plug both of my 12V rails into the video card easily.

My system works fine with it...

ASRock939 Bios 1.2, non-modded (so far)
AMD64 3200 Venice @ 2.50Ghz (250x10, 1.45V)
2x1GB Gskill ZX PC3200 DDR400 2-3-2-5 @ 1:1 (DDR500) 3-3-3-6 [2T]
8800 GTS 320MB "superclocked"
Fortron AX450-PN 450W RT
Seagate SATA 160 GB
 
PETEKW said:
resolved. The 8800 comes with a 12v rail combiner. It's a simple hack so that I can plug both of my 12V rails into the video card easily.

My system works fine with it...

ASRock939 Bios 1.2, non-modded (so far)
AMD64 3200 Venice @ 2.50Ghz (250x10, 1.45V)
2x1GB Gskill ZX PC3200 DDR400 2-3-2-5 @ 1:1 (DDR500) 3-3-3-6 [2T]
8800 GTS 320MB "superclocked"
Fortron AX450-PN 450W RT
Seagate SATA 160 GB
Click to expand...


I think its safe to say you are CPU limited...bigtime.
 
GEN3RIC said:
I think its safe to say you are CPU limited...bigtime.
Click to expand...

PETEKW said:
Right you are sir, BIGTIME. :mad:
Click to expand...

There shouldn't be any bottlenecking in single-threaded games with that setup. The FX-62 starts to bottleneck with 2 8800GTX's in SLI. You're not too far off the single-thread performance of the FX-62 with your chip and you're only running one GTS.

Nonetheless, a dual core processor would be the next logical upgrade for your setup.
 
PETEKW said:
resolved. The 8800 comes with a 12v rail combiner. It's a simple hack so that I can plug both of my 12V rails into the video card easily.

My system works fine with it...

ASRock939 Bios 1.2, non-modded (so far)
AMD64 3200 Venice @ 2.50Ghz (250x10, 1.45V)
2x1GB Gskill ZX PC3200 DDR400 2-3-2-5 @ 1:1 (DDR500) 3-3-3-6 [2T]
8800 GTS 320MB "superclocked"
Fortron AX450-PN 450W RT
Seagate SATA 160 GB
Click to expand...

What does this "rail combiner" look like? I ask because 12v2 only feeds the CPU through the 4 pin P4/AUX connector while 12v1 feeds everything else...including all the molex's.
 
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