520w psu for a 500w psu?

[rickzor]

This is my pesudo-dilema. In this pc, an athlon 64 3500+ clocked at 2.58 ghz, with 2 hdds, and a 7800gs clocked at 480\1400 that requires 20A from the 12v rail, i currently am using a q-teq 500w psu with 18A on the 12v rail. But now i have this shinny new trust 520w psu and im wondering if i should apply it or not.
The knowledge i am missing about psus is that if the 18A\12v rail specification in this case (qteq) are for each rail, or there is 18A for all the rails at once. Because this new psu i adquired states 12v rail1 12A and 12v rail2 16A.

Which one would provide more healthy\stable juice for this particular system? Because if in the qteq those 18A are shared for all the rails, then my graphic card won't as nearly as far from getting all it needs at full load, and with a 16A 12v rail provided only for it, maybe it would do better? Dunno, any thoughts would be apreciated ^^

Thanks in advance.

 

[rickzor]

Well all i can see there is

Qteq:
12v -> 18A



As for the Trust psu i have there

12v1 -> 12A

12v2 -> 16A

Should i assume the psu has 28A overall?
I don't really understand this.

 

[rickzor]

Hm, what i see is on the 12v1 144watts, and on the 12v2 193 watts, so, and if i got this right, i add 193+144, i got 337 watts, and with that formula ( w/v=A) i have 28 amps ?

337/12=28A

Or im doing this wrong by adding 144 and 193?

Thanks in advance

 

[doolittle]

Well that's the same as adding the 16A & 12A rails - It seems like you have a "bad" label, similar to this

Only the peak values are shown? You are left to guess what your real values are.

Compare to a "good" label:

this one has +12v@29A it is painfully ovbious.

If you wanted to guesstimate based on peak values, just take 70% of your 28A, that is ~19.5A. But don't max it, I stay under 80% of that which is ~15.7A.

use mpilchology (as stated in psu101) to get your +12v max:

eXtreme PSU calc[/url]"]System Type: Single Processor
Motherboard: Regular - Desktop
CPU: AMD Athlon 64 3500+ 2200 MHz Winchester
Overclocked: 2580 MHz, 1.5 V
CPU Utilization (TDP): 100% TDP

Video Card: NVIDIA GeForce 7800 GT 470 MHz
Video Type: Single Card

IDE HDD 7200 rpm: 2 HDDs

Fans
Regular: 1 Fan 120mm;

Keyboard and mouse: Yes

PSU Utilization: 100 %

Total: 227 Watts

(227-38 )/12 = 15.75A

Granted this is pure guesswork, you are spot-on for the dual-rail unit. If you have any issues, like blue screens / crashes when OC'd over long gaming sessions... just do what I did and use both of them.

 

[rickzor]

That sticky post from yours mpilchfamily is really good btw. And thanks for the help doolittle.
Yes, my label is much like the first one you've shown, which makes me wonder which psu to pick, although i've finally arranjed some spare time to test both of them (not much) and the dual rail one (Trust) seemed more stable when i overclocked the entire system, making me think that it might be a better option, but i'd rather test them a bit longer to make sure, because when i pick one of them, i must give the other one to my girlfriends pc, and i dont want to ask it back again if the one i picked fails me.

Will prime95 stress the psu enough (along with the system obsiously) in order to help me choose between the q-teq or the Trust psu ?

 

[doolittle]

Prime95 combined with ATItool's "scan for artifacts" function would stress the two most demanding system components. It also heats up your GPU pretty good so you can determine if your cooling needs are sufficient.

 

[rickzor]

I'ts a bit of a problem to make sure which psu to pick, but i think i already made my choice. I'll give it a go on the dual rail one for various reasons, well, for starters it has sata plugs and a power switch (that my other one didn't have), it's more stable when it comes to OCs, but mainly, it has a warranty
I won't get another psu for now, maybe when i'll upgrade the entire system, something that will happen somewhen in 2025.