Some observations after I removed my Kingston DDR400 kit and replaced it with a OCZ one.
Earlier I was running a OCZ kit (2 x 512mb) and the Kingston (2 x 512mb) in dual channel.
Now I'm running four OCZ modules in dual channel (2 x 512mb and 2 x 1gb) and set them at CL3 (CL2 is default).

Didn't use any flags at boot. System is running fine after 28 hours. No Mouse bug, no 10080 errors so far. Will report back once if I get them later (hopefully not).