MSI 970A-G45 will not complete POST

Question

Every so often, out of the blue, the system won't boot up.
Hitting reset doesn't help, disconnecting the power and letting it sit doesn't help.
The system powers on, begins it's POST, but after initializing the drives (HDD light flashes, CD ROM light comes on, goes off) it cycles again (right about the time it should initialize the video, it seems to loop back to the beginning of the POST - so I don't get any POST codes on the screen when this happens). It cycles through, initializes the drives again, and then starts over. IF however I pull either stick of RAM, it then will get past this, and continue on with the post. I can shut the system off as soon as I see the keyboard lights flash, re-insert the RAM, power up, and it's all back to normal. Resetting the CMOS does the same thing, but if I pull a RAM stick, then I don't have to set up the CMOS again. I have tried other RAM, but that didn't help. Any ideas?
Power Supply - CoolMax 600W - 5V24A, 3.3V24A, 12V1.8A+1.8A+15A, -12V.5A, 5VSB2.5A
Motherboard - MSI 970A-G45 model MS-7693, Bios V1.4
RAM - Transcend TX2000KLN-8GK DDR3 2000MHz 4G X 2 (8G kit) @ 1866MHz, 1.6V
AMD FX-8120 8 core processor @ 20 X 200MHz (4GHz)
ATI Radeon HD 6450 PCIe Video
2 X 500G Seagate SATA Hard Disk
500G Western Digital SATA Hard Disk
*****the 3 500G drives are in a striped RAID as a 1.5TB drive. This is the boot drive. RAID on motherboard. ***
1TB Western Digital Hard Disk
2TB Seagate SATA Hard Disk
2TB Western Digital SATA Hard Disk
LG SATA DVD Writer on MassCool card #1
LG PATA DVD Writer on MassCool card #1
Pioneer SATA Blu-Ray Writer on MassCool card #2
VIA 1394 Fire Wire card
2 X MassCool PCIe SATA/PATA/eSATA card
Adaptec 29320LPE PCIe Ultra 320 SCSI card (for U320 drives, not currently attached)
All-In-One USB card reader
Linksys Range Plus USB Wireless N 150 Adapter

Answer 1

Again, if it was the PSU, the board wouldn't "lock" in the looped state, and disconnecting all the drives would release it from any power induced failure if that was the issue, and as I posted before, disconnecting all the drives will not release the board from it's locked state. In my previous posts, I also stated that this failure happened before the system had all these drives in it. Another point, people have been underestimating power supplies for years - which is good for the manufacturers of high end power supplies, but bad news for our wallets. My power supply can support this system, plus about another 10 or more hard drives before things would get dodgy. This is something I have tested quite extensively since the late 80's when IBM PCs were still using 63W supplies, but everyone wanted a 150W in their "clones".
It should also be noted that the 5V and 12V rails are isolated from the voltages used by the processor and RAM. They aren't even connected to the same electrolytic capacitors.
in short, "If your car still rattles when the engine is off, the problem isn't the gas you are using!"
 PS - thanks for the advice so far, but since it's happened with 2 different supplies and under much less load, we need to stop focusing on the power supply. For the record, I ran the numbers again, and under 60% load (which is triple the average load on this thing when not editing video) I could add 10 more high rpm SATA hard disks and still be drawing under 600W. Yes, hard disks draw a lot of short term power at spin up, but power supplies can supply well beyond their maximum rating for short periods of time, so it balances out!
While I am at it, I thought I'd let you all "meet the beast".