Regarding the inability of the Gigabyte 8PE667 Ultra to run more than on stick of DDR333 memory: A FAQ in the support area of the Gigabyte website says the following-
"Q. 8PE667 series - Why cannot my DDR 333 be recognized correctly as 333Mhz but 266Mhz in 8PE667(8GE667) series mother board?
A. Based on Intel 845PE/GE chipset specifications, whether DDR333 can be supported appropriately depends on the CPU type you use. DDR 333 can be recognized correctly only when you use a FSB533 CPU. If you use a FSB400 CPU, then it's very possible that it can be recognized as 266Mhz. "
While this FAQ doesn't directly address the question of running more than one stick of DDR333, I haven't seen any comments which indicated whether or not a FSB533 CPU was used when this problem was reported. The AnandTech review did not state what the FSB of the CPU used in their evaluation was(correct me if I am wrong on this). Has anyone tried running more than 1 stick of DDR 333 with a FSB533 CPU on the 8PE667? If so were you successful?