Quote Originally Posted by Kenni View Post
I finally identified the issue, the onboard SATA 3.0 has issues. Once I moved the HDDs to the SATA 2.0 controller, the system got rock stable.

It didn't matter if I ran Ubuntu 10.10, Ubuntu 11.04 Alpha1 or CentOS (with kernel 2.6.18 or 2.6.37), they all crashed eventually.

I don't know if it's a local HW problem on my board, but if your Sandy Bridge Intel board is unstable, try to skip the SATA 3.0 ports to see if it helps.
Intel has stopped production of Sandy Bridge motherboards and is recalling all shipped motherboards due to SATA issues. Check with your manufacturer to find out how to return and replace yours.