Might pick up 680i to see bandwidth with these DDR2 modules stock voltage. It's known to be very low anyway, much lower than P35 can get.

3-2-2-1 1T 450MHz should be good. Phenom gets plus 11k read DDR2-1066 5-5-5-15 CR2 with ganged mode in Sandra (EVEREST doesn't support it properly) which is double what an Intel CPU/chipset would get at that spec.