Need more power for my 8800GT?

marcplante

Senior member
Mar 17, 2005
687
9
91
EVGA 8800GT wants 400W, but 26 amps at the 12 V rail

I have a coolermaster has 450W. The amperage chart in the documentation shows two 12V columns. Am I reading correclty to assume I combine the two to get my total amperage on the 12V rail? I'm reading correctly.

Looks like I have 34 amps peak (18 + 16), but only 22 amps continuous (12 + 10). I'm assuming that when a video card asks for power, they want it continuous. looks like 264W on the 12v rail.

system is:

MSI Neo8 Platinum
Athlon 38000+x2
2 G of RAM
6600 GT (going to EVGA 8800GT)
1 160G PATA HD (7200 RPM)
combo drive

How much power should I shop for? Might possibly upgrade the HD to a 320 or 500 gb SATA drive and add some RAM.

Thanks
 

mpilchfamily

Diamond Member
Jun 11, 2007
3,559
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26A or more is all the system really needs.

BTW you don't add the rails together to get total amperage. If the label doesn't tell you the total amperage or it doesn't show the total wattage on just the 12V rails then you won't know what the total is. The continues rating on the Coolermaster is the total aperage the PSU can offer on the +12v rails.
 

MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
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Can't find a 450w Coolermaster supply, so I severely doubt you have one :p You sure it's not 460w ? You simply look at the total wattage that can be put out by BOTH 12v rails, It's probably going to be around 240-300w, divide that number by 12, and you know how many amps it has total on the 12v rails. I think your system will hold up with the coolermaster, but it be nice to know EXACTLY what unit you have.
 

marcplante

Senior member
Mar 17, 2005
687
9
91
sorry, I should have been more specific.

it's an RS-450-ACLX/ACLY

DC output (from Documentation) My read is not enough.

3.3V 5V +12V +12V -12V 5Vsb
Peak 20A 35A 18A 16A 1.0A 2.5A
Continuity 20A 25A 12A 10A 1.0A 2.0A
Max | 191W | 264W | 12W | 12W |
Power 450W

Thanks
 

MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
5,664
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So yeah, 22a on the 12v rail. Not a whole lot but quite possibly enough. The CPU + GPU won't be drawing more then 100w each so it should be fine. You can at least try, and coolermaster should be of sufficient qaulity to make sure your rig doesn't go up in smoke.
 

marcplante

Senior member
Mar 17, 2005
687
9
91
Thanks for confirming my read of the documentation for the PS. Given the fact that EVGA is asking for 26A, I'll probbbly look into a bigger PS. I find that shortcuts compile over time, causing problems when you least have the time to solve them. I'd rather not worry about this too much, esp with two young kids in the household.

Thanks for the education, though.