12v amp rating question.

nan0_man · 06-30-08, 03:39 PM

this PSU: http://www.newegg.com/Product/Produc...82E16817341005
has 4 12v rails. Its sli certified but sli needs at least 12v@34A right? So, the above mentioned PSU wouldn't cut it, or would it?

do you combine the 12v rails to calculate Amperes when theres more than one?

thideras · 06-30-08, 03:44 PM

Well, depends what cards you are talking about. If you want to SLi 6800gs's, I'm sure it will handle it. SLi 9800GX2's? Doubt it.

WonderingSoul · 06-30-08, 03:46 PM

Quote:

Originally Posted by nan0_man

this PSU: http://www.newegg.com/Product/Produc...82E16817341005
has 4 12v rails. Its sli certified but sli needs at least 12v@34A right? So, the above mentioned PSU wouldn't cut it, or would it?

do you combine the 12v rails to calculate Amperes when theres more than one?

To calculate the combined 12V amperage among the rails is to find the total wattage produced by the unit and divide it by 12. Amps = Wattage/Voltage. However you can tell by looking at the label in the one side shot of the unit:
"+12V1 & +12V2 & +12V3 & +12V combined current < 50A Maximum"
So the total 12V is greater or equal to 50A. You should be fine for SLI

chop_wood · 06-30-08, 03:50 PM

you can't exactly combine the rails.
If you wanted to quickly guestimate maybe say by adding half the amps per additional rail. The correct way is finding the combined wattage for the rails(usually shows below the amp rating) then divide by 12.... so say you have a 500w psu... with dual 12v rails at 18amps and 350w combined on those rails, it would be 350w/12v which is 29amps ( not 18a+18a which is 36amps)

chop_wood · 06-30-08, 03:51 PM

guess wandering soul beat me too it lol

nan0_man · 06-30-08, 06:14 PM

Ahhhhh, now I see. Thanks guys.

nan0_man · 06-30-08, 06:15 PM

Quote:

Originally Posted by thideras

Well, depends what cards you are talking about. If you want to SLi 6800gs's, I'm sure it will handle it. SLi 9800GX2's? Doubt it.

2x7900 GT OC's...
2x SATA drives
1x C.C. Light
2x Pumps(little ones)
5 Fans
?

WonderingSoul · 06-30-08, 06:21 PM

Quote:

Originally Posted by nan0_man

2x7900 GT OC's...
2x SATA drives
1x C.C. Light
2x Pumps(little ones)
5 Fans
?

Shouldn't be an issue.

nan0_man · 06-30-08, 06:34 PM

niiiice.

06-30-08, 03:39 PM	Thread Starter #1
nan0_man Member Join Date: Jun 2002 Location: Jungle is MASSIVE	12v amp rating question. this PSU: http://www.newegg.com/Product/Produc...82E16817341005 has 4 12v rails. Its sli certified but sli needs at least 12v@34A right? So, the above mentioned PSU wouldn't cut it, or would it? do you combine the 12v rails to calculate Amperes when theres more than one?
	QUOTE Thanks

06-30-08, 03:44 PM	#2
thideras Banned Neckbeard Moderator Premium Member #3 Join Date: May 2006 Location: South Dakota	Well, depends what cards you are talking about. If you want to SLi 6800gs's, I'm sure it will handle it. SLi 9800GX2's? Doubt it. __________________ Desktop: Gigabyte Z77X-UD5H \| 3570k 4.6 GHz \| 32 GB GSkill Ares \| GTX 570 \| 180 GB Intel & 2 TB total \| Arch Linux and Windows 7 Main server: 37 TB raw disk \| 2x Opteron 6134 \| Asus KGPE-D16 \| 48 GB RAM \| LSI 8708EM2 \| CentOS 6.2 VM Server 1: Dell R510 \| 2x E5645 \| 128 GB RAM \| 4x 300 GB Velociraptor \| Xen Cloud Platform (XCP) VM Server 2: Dell R710 \| 2x E5645 \| 288 GB RAM \| 8x 300 GB Velociraptor \| Xen Cloud Platform (XCP) "That's not overkill, or a lot. That's just thiderastic." -txus.palacios Current projects: Rackmount Overkill (New) \| 30/45 hard drive server Articles: Rack Mounting 101 \| Dell Perc 5/i Throughput Benchmarks Past projects: Software RAID \| The Dragon Case My Website *Want to talk directly to all* the moderators at once? Call the Mod Hotline!**
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06-30-08, 03:50 PM	#4
chop_wood Member Join Date: Mar 2004 Location: San Diego, CA	you can't exactly combine the rails. If you wanted to quickly guestimate maybe say by adding half the amps per additional rail. The correct way is finding the combined wattage for the rails(usually shows below the amp rating) then divide by 12.... so say you have a 500w psu... with dual 12v rails at 18amps and 350w combined on those rails, it would be 350w/12v which is 29amps ( not 18a+18a which is 36amps) __________________ I5 2500K @ 4.9ghz\| Asrock z77 Extreme6 \| Crucial Ballistix Tracer 2x4gb @1866 \| 2gb MSI 6950 unlocked shaders 128gb Plextor M3 \| WD 11001FALS \| 620HX Corsair EK Supreme HF Nickel \| HD590 Sennheisers Laing D5 \| MCR-480qp \| EK SpinRes 4" ps1 lcd \| LIS2 Prem \| Lian Li PC2000v \| Yamakasi Catleap 27" \| Windows 8 HEATWARE
	QUOTE Thanks

06-30-08, 03:51 PM	#5
chop_wood Member Join Date: Mar 2004 Location: San Diego, CA	guess wandering soul beat me too it lol __________________ I5 2500K @ 4.9ghz\| Asrock z77 Extreme6 \| Crucial Ballistix Tracer 2x4gb @1866 \| 2gb MSI 6950 unlocked shaders 128gb Plextor M3 \| WD 11001FALS \| 620HX Corsair EK Supreme HF Nickel \| HD590 Sennheisers Laing D5 \| MCR-480qp \| EK SpinRes 4" ps1 lcd \| LIS2 Prem \| Lian Li PC2000v \| Yamakasi Catleap 27" \| Windows 8 HEATWARE
	QUOTE Thanks

06-30-08, 06:14 PM	Thread Starter #6
nan0_man Member Join Date: Jun 2002 Location: Jungle is MASSIVE	Ahhhhh, now I see. Thanks guys.
	QUOTE Thanks

12v amp rating question.

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06-30-08, 06:34 PM	Thread Starter #9
nan0_man Member Join Date: Jun 2002 Location: Jungle is MASSIVE	niiiice.
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