[RESOLVED] How do I choose a Power Supply (PSU)



New Member
I am building an 8 disk RAID and I've decided on the following hardware:

1 - AMCC 3ware 9590SE-8ML PCIe X4 Raid Controller
8 - Western Digital Caviar WD3200AAJS SATA 320GB Hard Drives
8 - Antec HD COOLERs
1 - Western Digital Caviar SE WD800JB 80GB Boot HD
1 - Amtrade 2001-ATX 13 HD server case
1 - MSI K9NBPM2-FID AM2 Motherboard
1 - AMD Athlon 64 LE-1620 2.4GHz CPU
2 - 1GB 240-Pin DDR2 800 (Total 2GB RAM)
1 - SONY Floppy Drive
1 - Sony 16X DVD ROM

How do I determine what I need in the way of power supply? I'm pretty sure I need 520 watts or better, but how many rails? How many amps on the various voltage lines?

Also, if anyone has any opinions about where I'm going TERRIBLY WRONG, I would love to know. :D

Obviously, I'm not going for extreme performance, I'm going for large capacity with with an emphasis on reliability and fault tolerance.


New Member
Shinma said:
May be of interest,
Justintime said:
  • eXtreme Power Supply Calculator Lite v2.5
Been there. That's why I mentioned that 520 watts or better seems appropriate. That site also says:
The recommended total Power Supply Wattage gives you a general idea on what to look for BUT it is NOT a crucial factor in power supply selection! Total Amperage Available on the +12V Rail(s) is the most important, followed by the +5V amperage and then the +3.3V amperage.
However, they don't indicate how you determine what adequate amperage on those voltage lines is, nor how to determine same. That's why I asked:
FuzzyBunnyFeet said:
... how many rails? How many amps on the various voltage lines?


New Member
Truthfully, I think they pop that up on there so you pay for the pro calculator. A good PSU should be able to give what you're needing.

As long as you don't get some cheapy PSU, you should be fine. Getting a 620 watt or something will do well. Just make sure you get something powerful, and not bare minimum.


Procrastinating Member
Get a good brand like Seasonic, Corsair, Enermax, PC Power & Cooling, Antec, Silverstone. Some of the generics cannot deliver their advertised output on a continuous basis.


New Member
After reading a rather comprehensive article about PSUs titled PSU Selection Guide (PSU 101-102) on the Xtreme CPU website, I've decided to go with the Corsair CMPSU-750TX.

The salient features that lead to this choice are:
  1. It is a Single Rail PSU.
  2. My power requirements should fall within the sweet spot of its noise level and efficiency curves.
  3. It has 8 SATA connectors.

I heartily recommend reading the PSU Selection Guide (PSU 101-102) article to anyone who is trying to figure out which PSU to buy.
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Procrastinating Member
Good choice. Their psu's are made by Seasonic or CWT, have tested very well, and IIRC, have a good guarantee.