Wait, I messed that up. The "eight contact" PCI-e socket is labeled JPWR2 ("to provide power to the CPU"), but I have nothing to plug into it. My power supply has a 6-prong plug that it says is for PCI-e...?
I just got this new mobo and the board has a PCI-e power connector that has eight contacts in it, but my power supply has a PCI-e cord that has only 6.
Are two just redundant and not used? Sharing a common ground out of manuf. laziness, etc., or have I got a problem on my hands?
Also, I noticed this mobo doesn't have the 2x2 square 12v power connector jack like most ATX cases, but just a regular 12v hookup like for the back of a disk drive. Is this normal?
If the mb is an ssi board, dual cpu xeon and opty usually is, it needs an eps power supply which has the 8pin mobo connector instead of 4 pin. You can get adapters to take the 4 pin to an 8 pin, it's not a pci-e plug.
Edit: I just checked out the MB manual, it looks like you can use the 4 pin or 8 pin version. Try it and see what happens, the pinouts are the same on 4 and 8 pin, 8 is just doubled so it won't hurt anything. It's funny that they use a standard 4 pin molex for the pci-e power but at least you can't get that one wrong
Edit 2: Here's a faq I found on it:
Q: Can I use a 4 pin 12V power connection for the CPU?
A: Yes, But in order to keep your system stable, we suggest you'd better buy a power supply with 8pins or need an adapter.
I just set up an MSI K8N Diamond Plus with AMD Athlon 64 X2 4200+ using a PC Power and Cooling TurboCool 510 Express/SLI power supply. The power supply has a 4-pin square 2x2 12V connector for the CPU and two 6-pin 3x2 12V connectors for the PCI-e graphics boards.
I was worried that I had bought an underpowered supply for the board, but there's plenty of 12V current (34A). Moreover, the 12V current is shared among all consumers in that supply, so you don't have to figure out how much the video "rail" vs. the CPU "rail" has available, etc.
Tech support at PC P&C told me that the 4-pin square 2x2 connector could be plugged into the 8-pin 4x2 header (either end) on the MB, and the system would work. I did, and it did. (MSI never did respond to my queries.)