PSU 400W 12V-20Amps

Soldato
Joined
17 Feb 2006
Posts
8,918
Location
Winchester
Solved: PSU 400W 12V-20Amps

Hi,

I just bought the new BFG7800gs agp and since i installed, I have been experiencing system reboots when playing BF2, CSS and Fear. I have come to realise the card requires 12V @ 20amps and my 400W psu only offers 12V @ 12 amps.
My system uses about 360W at the mo.

Does anyone know or recommend a 400W ish PSU that offers 12V@20 amps for around £50?

Thanks.
Sam

edit: Have just come across:
The UltraX Connect 500W @ http://www.overclockers.co.uk/acatalog/Ultra_X.html or

Tagan 430W with dual 12V rails-20amps or Tagan 420W I-XEYE with 12v-28amps @ http://www.overclockers.co.uk/acatalog/Tagan.html

Any recommendations?
 
Last edited:
Soldato
OP
Joined
17 Feb 2006
Posts
8,918
Location
Winchester
Thanks, preferring the Tagan 420W I-XEYE myself.

Btw, are there any dangers (i.e. blow up) if I carry on using that psu?

Really a pain, as the gfx card did not mention anywhere what it's power requirement was (nor do others) :(

Sam
 
Associate
Joined
31 Oct 2002
Posts
613
Sameer said:
SO I take it that for dual rails, I can add up both current values?
No, almost certainly not. The 430W modular Tagan with dual 12V-20A rails only supports a total of 26A combined. If running in dual rail mode you are limited to 20A on each rail (but the total cannot go over 26A). The Tagan's (and probably every make) automatically switch to single rail mode when the current draw on either rail exceeds the rated value (20A here).

For a given power, you won't get more available current on the 12V rails by going dual rail, you need to look at the combined maximum to compare to the single rail power supplies. The reason for having dual rails is to separate the supply to the system board from the supply used by the rest of the system (graphics, hard disks, etc.). That way, the system board and CPU get "cleaner" power (supposedly).

Either of those Tagan's should be fine, just check that they support the ATX standard your motherboard needs (the modular one certainly should as they are universal). Also check that they have enough power connectors for your needs (the newer power supplies come with PCI-express leads, SATA leads, etc. but less molex leads).

Hope this helps,

Martin
 
Soldato
OP
Joined
17 Feb 2006
Posts
8,918
Location
Winchester
I got the Tagan 420W Ixeye and no crashes yet. fingers crossed.

However I wish to point out that OCUK advertised the psu as 12V@28 amps and it is actually 12v@22 amps!!!! Advertising mistake there!!!

A bit of a lost cause really but why don't gfx card manufacturers state requirements of their cards in the first place? Would have rethinked spending £200+ on the gfx card and an extra £50 on the psu :(

Sam
 
Soldato
OP
Joined
17 Feb 2006
Posts
8,918
Location
Winchester
Would be grateful if someone could clarify stg for me:

THe psu has an earth cable that is supposed to be fixed to a motherboard screw? What's the logic behind that? I would have thought that I could connect that wire to my case only.
 
Associate
Joined
31 Oct 2002
Posts
613
Sameer said:
THe psu has an earth cable that is supposed to be fixed to a motherboard screw? What's the logic behind that? I would have thought that I could connect that wire to my case only.
I suppose that connecting an earth cable in this way guarantees that the case is earthed via the PSU. Without such a cable, the case is earthed only via the metal casing of the PSU (as far as I am aware). Given the Tagan's are painted black, perhaps this earth cable guarantees the earth is effective?

Anyway, since the motherboard screws normally connect directly to the case via a metal mount, using one would connect the earth cable to the case without need for finding another place to screw it. You can, of course, attach it directly to the case as you suggest.

Martin
 
Back
Top Bottom