Mixing ECC with nonECC RDRAM - What happens?

[NoodleKnight]

I have two sticks of 64MB PC-800 ECC RDRAM. I still have two more slots that are just using continuity sticks right now. Since RDRAM is pretty much dissapearing, and since ECC isn't that necessary, I'm thinking about purchasing two more sticks of nonECC RDRAM to fill up the last slots.

What I'm wondering is, what happens when you use nonECC with ECC sticks? Does the motherboard force all the ram modules to run in nonECC? or run ECC whenever applicable? Or will it just not work?

Thanks in advance,
NoodleKnight