Hello,
I have similar problems, HW being Atom 310 on a Intel based motherboard, 2GB RAM, Sil3124 raid controller. No messages at all, nowhere.
Sometimes, it crashes after a couple of minutes, sometimes after a couple of hours. At best, I was able to have it running one full day.
Today I am installing a brand new debian 7 on the same hardware to see if this is a hard or soft issue. I am running tests now.
Do you think that compiling your own kernel may help things ?
Thanks,
Cybearman