Prescott @ 4Ghz+. PSU recommendations...

[Touche Turtle]

I've been told that my current PSU (Hiper 520w) is probably limiting my overclock (Prescott @ 3.9Ghz) due to its weak 20a 12v rail.

Can anyone recommend a good PSU that will definately not stand in the way of overclocking my chip, will hopefully last through my next CPU/mobo upgrade, and isn't total overkill on price and performance please?

Thanks.

[Entsafter]

I've the same problem with a levicom 500w psu: 301 12v rail, but only 11v @ load...
You can try to run your System with 2 psu's, 1 for the mobo and 1 for graphiccard.

[AKURA]

You're mb's power maybe at it's max...Your better off with a better cooler and providing some passive cooling to the mosfets rather getting more power than wont take you anywhere.

[Touche Turtle]

You're mb's power maybe at it's max...Your better off with a better cooler and providing some passive cooling to the mosfets rather getting more power than wont take you anywhere.

I'm using an XP-120 and have fitted heatsinks to all 'fets on the mobo so hopefully cooling isn't the issue. The only thing I am considering is a capmod - I have the capacitors waiting to be fitted - but don't want to saw my case & perform major soldering surgery unless all else fails! Infact this was to be my next approach until I heard someone say "for a Prescott at 4GHz+ you need a PSU with a > 22a 12v rail."

Ideally I'd like to try my system with a more suitable/stronger PSU before buying one, just incase it turns out not to be a 12v rail issue that's preventing my overclock, but as always I've gotta make that leap of faith! (I will, however, not be pleased if a nice, new & spangly PSU with a monster 12v rail doesn't improve things). :slapass: :)




You can try to run your System with 2 psu's, 1 for the mobo and 1 for graphiccard.

I considered trying this too, but wasn't sure how to go about it, and I haven't got room for 2 PSU's in my case anyway.

[AKURA]

I'm using an XP-120 and have fitted heatsinks to all 'fets on the mobo so hopefully cooling isn't the issue. The only thing I am considering is a capmod - I have the capacitors waiting to be fitted - but don't want to saw my case & perform major soldering surgery unless all else fails! Infact this was to be my next approach until I heard someone say "for a Prescott at 4GHz+ you need a PSU with a > 22a 12v rail."

You dont need that much power necessarily. I was using a 400W Fortron priming a prescott at 4.2Ghz on air cooling. The psu has 2 separate rails 14amp for the cpu alone and 15 for the rest of the system and it manage to do it more stable compare to my 460W zippy. So imo cooling will give you more boost than power. Because the psu has a 120mm standalone cooling fan compare to the zippy with only an 80mm fan to exhaust all the heat.

Have you ever considered strapping a 120mm Delta fan with 220cfm on your XP120? Try that and I guarantee you 100mhz more on your cpu clock speed. :D

[Touche Turtle]

You dont need that much power necessarily. I was using a 400W Fortron priming a prescott at 4.2Ghz on air cooling. The psu has 2 separate rails 14amp for the cpu alone and 15 for the rest of the system and it manage to do it more stable compare to my 460W zippy. So imo cooling will give you more boost than power. Because the psu has a 120mm standalone cooling fan compare to the zippy with only an 80mm fan to exhaust all the heat.

Have you ever considered strapping a 120mm Delta fan with 220cfm on your XP120? Try that and I guarantee you 100mhz more on your cpu clock speed. :D

Thanks Akura, yes, I'm now holding off buying a new PSU for now - I want to remount my XP120 and fit a Delta 120mm 190cfm fan I have lying around. Need to come up with a 12v/7v switch or a diobus first though - I'm not living with it on full blast (previously had a Delta SHE 80mm on full whack and still haven't recovered my full hearing yet!).

Reading about your 400w PSU that you used to successfully prime @ 4.2Ghz - it does have 2 12v rails though, totalling 29A (compared to my 20A total), also your dedicated CPU rail would guarantee cleaner power for the CPU which would help.

I still think it *could* be PSU related, although I now think it's worth trying some other things first, as you suggest. Thanks.

[AKURA]

Yup np, 120mm Delta at 5V would be more tolerable compare to 7V/12V and could still manage to push an enormous amount of air. When you purchase a psu just make sure it's a known brand and that you know your getting some serious power even at a very high temperature surrounding it. :toast:

[Twisted-net]

I have the same problem i got a 3.2E cpu and 4.0Ghz is stable until the point i'm stressing my gfx card. (see my post in intel section)

After some searching im going with the 500w zippy ( 32A @ 12V )
That should fix my problem that my 420w psu cant handle.
(had 22 amp @ 12v) so maby yours is a little low there.

I sinked my mosfets watercooled my cpu and so on..
dual prime stable 12h and more, but put prime and 3dmark loops on together
than a reboot ===> short on power.

[Touche Turtle]

Twisted net, Interesting - have you got any more info or a link to that "Zippy" PSU please? Thanks.

[Twisted-net]

Twisted net, Interesting - have you got any more info or a link to that "Zippy" PSU please? Thanks.

Zippy/emacs is a company well known in the server industry,

they have some nice psu's (as good as a OCZ powerstream, many will agree)

Link (http://www.zippy.com/P_PRODUCT_LIST.asp?pcp_rfnbr=3&pcp_name=PS2/PS2%2b%20single&lv_rfnbr=2)

Im going for the 500w because its kinda small the others are a bit bigger and its 135 euro here in belgium.