If this has only started happening after adding the new RAM, it's likely that, rather than there being a problem with the RAM itself, there is a problem with the way the ACPI system is working with it behind the scenes.
I don't think it's much to worry about, I expect it will be solved in a future BIOS update. I get a tonne of these on my old SIS based P4, but i've never had a single bluescreen or freeze.