single channel usually runs much better and you need less vdimm to get more results quite often. imo it shows well how the chipset limits the ocs.

how much vmch did you try?
btw, did asus ever fix the bios bug with high fsb speeds?
i cant boot with 2050mhz on p5k3, even in single channel and even with high vdimm and 888 when the stick can do 2025 completely stable with much less vdimm. if i boot at 2ghz and use setfsb i can get to 2050 without any problems...

im still using 0604 i think, whats the latest bios for p5k3 and is it good?