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Chat => Entertainment & Technology => Topic started by: Quixoticish on October 14, 2007, 18:35:10 PM

Title: PSU queries
Post by: Quixoticish on October 14, 2007, 18:35:10 PM
My better halves once broken, and fixed PC is now borked again. However I think its the PSU but I need help deciphering which PSU to pick up. Now, stupidly she plumped for an X1950 GT which ATI recommends needs 30A on the 12v rail minimum to function correctly. Shes running on an Antec Truepower 480W and on the side of the PSU it lists 28A on the +12V rail and 1,0A on the -12V. Now what does that mean in English, and given that shes also running the usual accoutrements such as CD/DVD-RW, floppy drive etc is she pushing her luck? (Im dubious about Antec PSUs anyway, Ive had two go pop on me in the past and this is at least two or three years old). Im thinking about replacing it with this anyway:

http://www.ocztechnology.com/products/power_management/ocz_stealthxstream_power_supply

Now this lists four different 12V rails, each putting out 18A. Do I add those figures, so 4x18 = 72A total on the 12V rail? Or am I missing the point completely and do I need something that puts out 30A on one 12V rail?

Sorry for the rather random question; the last time I scratch built a PC the PSU wasnt even an issue, you just whacked in the highest wattage you could get.

Title: PSU queries
Post by: knighty on October 14, 2007, 19:02:42 PM
some/most psus have a little switch on them so you can combine the 12v rails.... so yes 4x18=72... but some dont :(

give me a min and Ill google for the psu power calculator i used before...

http://www.journeysystems.com/?powercalc

go there.... last time I used it It worked out at just over 800w... so got a 1000w just to make sure :)

(tis a hell of a beafy system tho!)
Title: Re:PSU queries
Post by: Quixoticish on October 14, 2007, 19:05:01 PM
Cheers Knighty. To be honest Im lost with all of this... the only thing is the PSU needs to work on the older AGP/ATX motherboards like the Epox 8RDAE and Abit NF7-S 2.0; Im being wary of that as Im not sure if the connectors have changed.

Tempted by this for future proofing assuming itll work on older motherboards...

http://www.silverstonetek.com/products/p_spec.php?pno=da650&area=usa

54A on one combined 12V rail?

Title: Re:PSU queries
Post by: Quixoticish on October 14, 2007, 19:23:26 PM
Current PSU readings from the BIOS if that means anything to anyone, its double dutch to me:

Vdd(v) = 1.61V
Vcore(v) = 1.64V
Vdimm(v) = 2.72V
+5V = 4.99V
+12V = 11.79V
Vagp(v) = 1.52V
-5V = -4.99V
VBAT(v) = 3.08V
5VSB(v) = 4.96V

And from speedfan:
VCOREA = 1.62
VCOREB = 1.65
+3.3V = 2.74
+5V = 4.97
+12V = 11.80
-12V = -7.10
-5V = -5.00
+5VSB = 5.51
VBAT = 3.10
Title: PSU queries
Post by: knighty on October 14, 2007, 20:44:20 PM
youre 3.3v and 12v are off quite a bit.... the others are only off a bit so its not a big deal... theyre always up or down a bit tbh (normaly down)

and you can get an adapter for a couple of quid to swap between the 20pin and 24pin motherbord conectors :)

(i think its 20pin vs 24pin... but thats from memory... its something like that!)

p.s. that psu you kinked looks good to me !
Title: PSU queries
Post by: filbert on October 14, 2007, 21:01:15 PM
Check this thread out:
http://www.tekforums.co.uk/posts/list/9756.page
Title: Re:PSU queries
Post by: Quixoticish on October 14, 2007, 22:38:56 PM
Thanks guys. Filbert, that OCZ one you linked looks the buisness so I may order that.
Title: PSU queries
Post by: Quixoticish on October 14, 2007, 22:43:29 PM
Quote from: knightyyoure 3.3v and 12v are off quite a bit.... the others are only off a bit so its not a big deal... theyre always up or down a bit tbh (normaly down)

and you can get an adapter for a couple of quid to swap between the 20pin and 24pin motherbord conectors :)

(i think its 20pin vs 24pin... but thats from memory... its something like that!)

p.s. that psu you kinked looks good to me !

I cant seem to find the converter you are on about Knighty. I can find 20 pin to 24 pin ones but none that work the other way around for older mobos.

I also keep reading something about newer PSUs not providing -5V anymore and that may be a problem.

 :? Bloody hell.
Title: PSU queries
Post by: knighty on October 14, 2007, 22:52:57 PM
hmmm, I cant find any either now :(

maybe they dont bother doing them anymore as theres not enough demand ?

iirc most new/decent PSUs some with a 20pin connector with a little 4pin block that fits onto it to make it 24pin....

or if theres room around the connector on the m/b you just plug it in and the extra 4 stick out on one end not plugged into anything :)
Title: PSU queries
Post by: Quixoticish on October 14, 2007, 23:06:09 PM
Quote from: knightyhmmm, I cant find any either now :(

maybe they dont bother doing them anymore as theres not enough demand ?

iirc most new/decent PSUs some with a 20pin connector with a little 4pin block that fits onto it to make it 24pin....

or if theres room around the connector on the m/b you just plug it in and the extra 4 stick out on one end not plugged into anything :)

Ahh, nice one, that wont be an issue. The only hurdle I know have to jump is this stupid -5v thing. Is it essential? Am I just borked and will have to pick up a second hand old PSU on fleabay?
Title: Re:PSU queries
Post by: Quixoticish on October 14, 2007, 23:38:35 PM
Ordered this one, its the only one I can find that still does -5v.

http://www.scan.co.uk/products/productinfo.asp?WebProductID=243645

Shes getting a new PC for Christmas from me I think, I cant be arsed with this incessant tinkering anymore.  :(
Title: PSU queries
Post by: filbert on October 14, 2007, 23:40:26 PM
The OCZ is actually a pc power and cooling, great psu:
http://www.pcpower.com/products/viewproduct.php?show=S61EPS&view=about
Dont worry about the -5v, it almost certainly wont be needed:
http://www.playtool.com/pages/psuconnectors/connectors.html