I am having a similar problem with my Ultra D and TMSP UTT-CH chips.
I can boot with one stick and the jumper at 3.3v, but when I put two sticks for dual channel operation, I only can boot up with the jumper in the 4v position...
Any sugestions??
I have tried several BIOS (now running 510-2), reseting CMOS dont work, take off the BIOS battery dont work. I think that one of my sticks has a bad SPD rom, it could be for the high voltages, but havent passed them of 3.7v, and for 24/7 running I use 3.4v for 264 Mhz... and the sticks and mosfet are actively cooled...
Any suggestions of I cant boot up with two sticks and jumper in 3.3v? Because I want to run 24/7 with Bigtoe trick, but I only can boot up with one stick using the trick as well...