I have a Coolmax CX-550B, and I was wondering if it would run these specs without a problem:
74gig Raptor drive
160gig WD IDE drive
Pentium D 2.8
1 dvd burner
I know Nvidia states you need at least 26A on a 12v rail, however, I have 18A on two twelve volt rails, do they combine and count? Thanks. If this does not work, can you reccomend a cheap one that would work?
It should work. Do you see the chart on the website you linked to? Under the +12v rails is a wattage number. Your unit supplies 420watt to the +12v rails. In order to get your amps, divide that by 12. In this case 420/12 = 35 amps. You're good to go.
The other company is "Ultra" you know, with the X-connect, can't pick up a computer magazine without one of their ads. Thank you though, I have read on other forums that since the 12V rails are split and run at 18A a piece its not good, they should run 26A a piece, not together, is this true?
The recommendation is for 26 amps on the combined (or single) +12v rail(s). It doesn't matter how you get to 26 as long as you get there. Some people say that a single +12v rail is more efficient than multiple rails, whether or not that is right, I don't know. If you want more in depth info, head over to the PSU, Cases and Case Mod section and read the PSU FAQ sticky. A lot of good stuff in there.