Question on PSU

[texsized]

frankly i don't know much about PSU's so i need some input here. what confuses me is the AMP on 12v power part. is a 30A better than a 20A? they are both 550watts. here are the full specs.

what about brand does somebody something about these 2 brands, which would be more reliable. my budget peaks $25 on psu.

1st one
CHIEFMAX 550W P4 & AMD ATX Dual Fan Power Supply SATA

115V ~ 10A/60 Hz
230V ~ 6A/50 Hz
+5V at 32A
+12V at 30A
+3.3V at 32A
-5V at 1A
-12V at 1A
+5VSB at 2A

2nd one
XPOWER 550 Watt P4 ATX Dual Fan Power Supply SATA

AC Input 115/230, 3A/2.5A, 60Hz/50Hz
Max Load +3.3@28A,
+5@40A,
+12@20A,
-12@0.8A
+5vsb@2A
-5@0.3A

[zep516]

no 30 amps is not better then 20 amps,the amp rating 30 amps will supply about 28 amps at +12 volts .The 20 amp rating will supply about 18 amps to requried devices at 12 volts.IF you are changing a unit you need to match these amp and voltage relationships as close as possible to the orginal you also should know the amount of amps needed in your set up.Most of the amp draw [current draw]is consumed by fans ,drives,ect. i=e/r where i is amps e is voltage r is resistance.

[texsized]

no 30 amps is not better then 20 amps

bottom line are you saying am better off with a 20A psu than a 30A @12V? (kinda like the closer to zero the better?)

this stuff is for a new rig am putting together; i'll check on the power ratings on the periphals @ home tonight.

[zep516]

texsized i think either unit will work,go with cheaper for budget.

[galena1]

Hi tex - A useful little tool at the link below that may help with power supply choice. Regards.

http://www.jscustompcs.com/power_sup....php?cmd=INTEL

[glad2bhere]

interesting and insightful link. another one
http://www.extreme.outervision.com/index.jsp

[Basementgeek]

my budget peaks $25 on psu

I think you need to increase your budget. A cheap power supply is exactly that, cheap. They use cheap components.

If a power supplies just dies, no real problem you can get another one.
However other things can wrong, such under regulation -to much voltage, they can suffer from poor filtering, allowing to much AC ripple.

A faulty power supply can take out everything in your PC, drives, CPU, MOB, cards,RAM. You could end with a 20 lb door stop.

BG

[zep516]

basementgeek is right. spend as much as you can on the power supply it runs everything.The more expensive supply's have more wattage they can run cooler as there not under stress to provide power when needed,the voltage/current relationships are close in all the supplies as they became standard for computers.as basement said the better supplies provide filtering on the dc out put voltages and regulation that means +5vdc stay's at plus 5 an so on even if input voltage level drops these supplies can regulate the dc out put to devices and system board with out this regulation eratic operation to much heat and faliure can occur.Tex thanks for topic it's made me review my power supply knowledge. zep.