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Dual rails?

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mantralord

Member
Joined
Dec 14, 2004
My Abit AV8 supposedly needs at least 25 amps on the 12v rail to work right, and I only have 18A on my Thermaltake 480 and having issues with startup etc. So I guess I need a new powersupply.

So I'm kinda confused with dual 12v rails, I've searched and can't quite find the answer...is it safe to assume that the total amps on the rail are the sum of all the 12v rails combined? Because I need at least 25 supposedly to power this thing, and most seem to have dual 15A, etc.
 
your problem isnt too small of a powersupply, the thermaltake should handle it fine. where did you see you need 25amps?

edit:

from the manual, the only mention of powersupply specs i can find is this:
NOTE: it is recommended to connect a powersupply with 350W, 20A +5VDC capacity at least for heavily loaded system

im almost certain that powersupply should be able to handle that motherboard with no problem
 
Last edited:
zip22 said:
your problem isnt too small of a powersupply, the thermaltake should handle it fine. where did you see you need 25amps?

They answered it in Abit's forums...and many people have the same problems i'm having too until they upgrade to one with more amps on the 12v.

My problem is basically that it takes several tries to start up the machine...what it does is the fans spin up and in about 3 seconds it shuts off. I have to keep turning it on for like 3-5 tries before it starts.
 
thats interesting, was there any explanation as to why the motherboard required so much power?
 
zip22 said:
thats interesting, was there any explanation as to why the motherboard required so much power?

No, but I'm guessing it has something to do with the fact that Abit sucks now.

But anyway, I have 2x512mb Patriot PC3200 (the kind with TCCD chips), and I can't reach stable past 230 fsb with 3-4-4-8 timings at 2.8v. I posted that and abit's forum replied that I dont have enough amps in my 12v to power it...

Also, my 939 Winchester 3000+ can't even reach 2.25 ghz stable...
 
Were I in your shoes I would consider the Fortron 550 that has the single 28A 12V rail. There is another variant that has dual 12V lines, but I suspect your application would benefit more from the single really stout line.

You might also email some power supply manufacturers and get their opinon on single vs dual 12V lines for your application. It sounds as though your setup challenges the usually ~15A 12V capablity of typical supplies, and I'm not sure a second 15A circuit is really what you need.
 
I was thinking either the Enermax 550W or the OCZ Powerstream 470W.

If anyone objects to those let me know...
 
Ad Rock said:
Those PSU's are starting to become the best in the game in my opinion.

They haven't quite convinced me yet, but I'll recommend them anyway. I'll second the suggestion for the Fortron unit Larva mentioned - FSP550-60PLG, though it has a single 36A 12v rail rather than 28A. Finally, I'll put in a plug for the new kids on the Newegg block - Zippy. They have several models that will work, but though I have heard nothing but good things about them, most of their units are single fan designs.

I'm giving some thought to grabbing a Zippy for my next build and seeing how good they are in person. If I can find one in Canada, that is.
 
Do you have your fans connected to the mobo pins? perhaps that is causing some power issues with the board. I would suggest connecting your fans directly to the psu and see if that helps your bootup problem at all. Also, what is your 12V rail reading at once you get into windows?
 
facialicious said:
Do you have your fans connected to the mobo pins? perhaps that is causing some power issues with the board. I would suggest connecting your fans directly to the psu and see if that helps your bootup problem at all. Also, what is your 12V rail reading at once you get into windows?

All my fans are hooked up directly to the psu.

The Abit AV8 doesn't have a 12v reading, because as I said, Abit sucks now. Maybe I'll go to Radio Shack one of these days and get a multimeter.
 
Oklahoma Wolf said:
I'll second the suggestion for the Fortron unit Larva mentioned - FSP550-60PLG, though it has a single 36A 12v rail rather than 28A.

Sorry my bad, the 28A 12V capability of the 530 fogged my mind. 36A it is (and that 36 Fortron amps, which are the real thing).
 
larva said:
Sorry my bad, the 28A 12V capability of the 530 fogged my mind. 36A it is (and that 36 Fortron amps, which are the real thing).

Ooh, Fortron amps...*fap fap fap*

So I have Fortron 550, Enermax 550, or OCZ 470 to choose from...I wonder which?

Also, the Fortron one has a bit lower amps on the 3.3/5v lines than the other PSU's...do the amps on those rails matter much?
 
Not if you're running a 12v based motherboard, which is most of them these days.
 
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