Asus P4P800 – Twinmos/Winbond incompatibility?

[PhAzE]

Hi, I’m using 2 x 256mb twinmos dimms with ch-5 winbond chips and have run into some overclocking troubles. In single channel mode the computer works happily with a fsb of up to 271MHz, mem @ 217MHz (5:4 ratio).

In dual channel mode with a 1:1 ratio the machine boots at 244MHz+ fsb’s (2.85v). However, when I try to use dual ddr mode with a 3:2 or 5:4 memory ratio the computer will not boot with fsb’s above ~256-257MHz! (171 or 205MHz mem, voltage inc has little effect).

Currently the ram is running single mode at 2.55v in slots 2 & 3 as it would not boot at 271 in slots 1 & 2. I’m using a standard Asus P4P800 with the latest bios (1008 I believe) on a revision 1.02 board.

I’m pretty sure Asus lists the ram as compatible with the board but fear that perhaps at higher clock speeds it is not.

Any help or suggestions for getting dual ddr and memory ratios working together are appreciated, Thanks.