It's not that hard.
I have 4 drives loaded in the rear bays and 2 x 5 Way SATA Hotswap bays in the 6 front 5.25 inch bays. 14 Drives. And yes, they are on a single 420w PSU along with the motherboard, Athlon XP 2600+. and 5 80mm fans. Not much else though.
!!!!!! Holy crap!
Let's pick a random typical hard drive, a Seagate 120GB SATA: http://www.mittoni.com.au/catalog/product_info.php/products_id/1690 It lists maximum current draw as 2.8 A on the +12V line. Multiply that by 14 drives and we get __39.2 amps__.
Now, lets actually pick my hard drives shall we?
Max current draw on the 12v line is 1.56A at spinup, dropping to 600mA at seek and 556mA at Idle.
So _worst_ case is 21.84A for about 2 seconds (which does actually exceed the PSU ratings by nearly 3 amps). This machine only gets power cycled about once every three months and I did actually monitor the 12V rail with a CRO to check specs and ripple and they never budged.
Worst case running load is 8.4A which leaves ~10A on my 12V rail for my motherboard. Ample.
Now let's pick a random 420W power supply: http://www.newegg.com/app/viewproductdesc.asp?submit=Go&description=N82E16817103445 Note how it's +12V output is rated for only __15 amps__.
Now lets pick my power supply http://www.wasp.net.au/~brad/p1000256.jpg
So yes, on spinup I'm exceeding my 12V rail by 3 Amps for about 1.5 Seconds (Which this supply has amply proven capable of handling). Outside that I don't see an issue.
Your numbers might differ a bit. But it is NO surprise that your drives are failing. The surprising part is that they and your power supply have worked this long.
I never said anything about failing disks! In fact, if you check back you will see me commenting I have a bucket load of Maxtor Maxline-II drives in there that have been flawless to date. (In fact I have just ordered 25 more, 15 for me and 10 for a mate. That should increase the sample a little) They all sit at below 40 Degrees C and the PSU remains quite cool. (I'm an electronic technician by trade and have several thermocouples I use to verify measurements).
Here is the reason the drives stay nice and cool. http://www.wasp.net.au/~brad/p1000250.jpg
--
Brad
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