power supply question

I'm sure that by now you're all sick of my power supply questions. Too bad! I just need some thoughts on this: for an X2 Athlon64 5400+ with one HD, 2 CD/DVDs, 1 FDD, 3gb DDR2, and a 512mb 9600GT video card and 4 or 5 case fans, which of these two PSUs would you pick and why:
PSU1: 600w; 4 x +12v @ 18a each; +3.3v @ 36a; +5v @ 30a; 5vsb @ 3a; combined power for +12v 580w; 5 year factory warranty
PSU2: 650w; 2 x +12v @ 20a each; +3.3v @ 30a; +5v @ 54a; 5vsb @ 3a; 3 year factory warranty

Thanks.

(I'm not even sure that I need to upgrade my current PSU; it seems to be running fine, but it doesn't hurt to have a plan)

Link to PSU1 datasheet PDF http://www.supertalent.com/support/download/Flyer_final 600-700.pdf
Link to PSU2 web page http://www.epowertec.com/zu650w.html
PSU2 is listed on the AMD/ATI recommended/certified list; that's how I found it.

 

Why the off brand choices. I never heard of either one until today? If you want something reliable get a name brand Antec/ThemalTake/PC Power&Cooling heck even an Enermax over either of those two. Its your money. The first one has 4 - 12v rails and a 5 year warranty, and according to Newegg its pretty heavy, so it will have beefy caps and sinks.

 

Because of the weak state of my wallet. Yeah, I know the good brands are the way to go, but I just don't have the funds to shell out $150 or more for a top notch PSU. I'm not sure I need a top notch PSU. I might be wrong, but even the high end PSUs don't have 'insurance' warranties where they cover any damages to hardware if said damages are caused by the power supply. You know, like most battery backup UPS units and the higher quality surge protectors will cover up to a certain amount of damage if it's proven that the damage was caused by a power spike or surge or outage or brownout...

The first one is the one I'm most likely to get. But the second one isn't really an off brand. ePower/Topower/Zumax have been making power supplies for years that are sometimes sold under other names (much like FSP does with their PSUs).

Does 4 rails at 18a each make that much of a difference compared to 2 rails at 20a each?

 

Yes, the 4 rails are a better choice because they allow you to split up your power into 4 segments of 12v devices. The total amp draw on each rail would be limited to 18 or similar to 3or4 hard drives pulling max power (initial spinup draws 3.5-5.5 while already spinning draws 1-2.5). But you would not put 4 hard drives on each rail so with 2 to one rail and 2 to another, along with 2 roms on the third and fans or what ever on the fourth, you would really be soft on the demand for power, putting less starin on the unit overall.

2 20amp rails on the other hand can also limit just whats hooked up in a tall case, since there are only two, you have to hook one up to all the connections at the bottom and one to the top devices. You've probably run into this before, I know I have. Sharing the connections from only two rails can mean using some splitters to connect between the two sections of a case tower.

If I had my druthers I would rather have 4 rails with two or three connectors each, than 2 rails with four or five (a floppy counts as one too). It just gives you more options when spreading the amp draw around.

 

I'm not sure how much it varies from manufacturer to manfacturer, but the 9600gt 512's minimum specs are 26a on a 12v.

You may want to beef up your selection.

 

Thanks Appz; good explanation. I was kind of leaning toward the 4 rail PSU anyway. However, Lanfear above brings up a good point. I know that because these are multiple railed PSUs, that it's a bit different. I have never seen a multi-railed PSU with over 22a per rail, and those are rare. Most are in the 18a to 20a range, with 18a being fairly common. In the scenario where a card requires 26a on the +12v, I think that applies to single railed PSUs; when referring to multiple rails, there's a combined +12v output and I'm sure it's over 26a on any PSU with 18a per rail running 2 or more rails. The 600w PSU referenced above with 4 rails is marketed as an SLI/gaming PSU so it must be strong enough to run two high end video cards. I know you don't just say "4 rails at 18a each equals 72a combined", but I know it would be somewhere in the 50s. I'm not sure how combined amperage output is computed so if someone could shed some light on this, that would be great.

On a different note: I came across a PSU with a single rail of 36a. There's been alot of talk recently about how one beefy rail is 'better' than several less beefy rails. For example: PC Power & Cooling has expensive PSUs with single hefty rails (look here: http://www.newegg.com/Product/Product.aspx?Item=N82E16817703005 with 49a on the single 12v line). It seems to me that multiple rails is better for stable, even power draw: one rail for MB/CPU, one for video, one for HD, and one for everything else like fans, optical drives, floppy drive.