I got this MB for Christmas and set it up last week. My ULTRA PSU only has a 4 pin 12V connector. It works fine. My CPU is a Phenom II X2 555. I tried to get the other 2 cores unlocked but couldn't. It would post but not boot into windows 7 64 bit with 4 cores enabled. I was able to get 3 cores running by disabling core 1 and enabling cores 2 and 3. Thinking I had a PSU problem I bought an new one (mine is about 3 years old but was brand new). It was an ANTEC 500W from Staples. That had the 8 pin 12V connector. The strange thing is that PSU would POST but would not boot into Windows. Not even with just 2 cores enabled. I returned the PSU. Just to be sure I was getting enough power to the 8 pin connector, I bought an adapter that merges the PSU's 4 pin connector and a 12V (harddrive/cd power) cable into an 8 pin connector for the CPU.
Make sure you don't use the 6 pin video power connector. It doesn't work (trust me!) because it's wired opposite the 4 or 8 pin CPU connector. If you have access to a voltmeter, you could check your HD power connectors to see if there's power there.