Mixed RAM on MSI K8N Neo Platinum

[Boris25]

I've just bought a 512mb Elixer module which I installed with 2X 256mb Corsair Value. The problem is that although they work, they will only run together at DDR 333, rather than 400, which is what they are rated at. I know that the problem is with the timings; Corsair= 2.5 3 3 7 Elixer 3 3 3 8. My PC runs them together at the Corsair timings, which I presume is why it has to clock the Elixer down to 166MHz thus dragging the rest with it. O.K, I thought, I'll just run them all at the more relaxed 3 3 3 8 timings; I figured that the Corsair would have no problems doing this. Wrong; my PC wont boot at all and I have to reset CMOS and start over.
Can anyone help me? Any advice would be appreciated.

[Shorty]

As far as I am aware and remember (without looking it up).. that board only supports two dimms full of memory for DDR 400 performance. Il check my manual later.

[Boris25]

...just looked; it only supports upto 2Gb of DDR400 (as opposed to 3Gb of DDR333) but you can use all the slots...so theoretically they should be working!?