Running ECC memory in a non-ECC system

I have to ask, everyone always says to get the right memory for your system as you wouldn't want to run non-ECC in a server or to run ECC memory in a regular desktop.

What do you think would happen if you were to run ECC memory in a regular desktop system?

I have run ECC memory in a non-ECC motherboard and non-ecc in a server board, but those motherboard manuels said i could put in either. many motherboard manuels and manufacture web stuff now say NON-ecc memory, (for the desktop motherboards) as if it is specific.

if it was one of them boards that is pretty specific about it, well they should know?

Best case is it would work but not do additional error checking. The other way around (putting non-ECC memory in an ECC motherboard) wouldn't work because the board requires that extra functionality.

I didn't have luck to run ECC memory on a desktop board for long time. I think that last time when it worked were P4 times but I didn't try it on latest boards. Point is that most boards on cheaper chipsets won't boot at all with ECC memory and some high end chipsets will run only if you use rank 1/2 ECC kits.