i remembered one thing where i work we had a miss behaving fan for a dell r540 and its got solved after i updated the bios. for my case with the r430 its already on the newest. but for funs sake i reflashed both the idrac and the bios fw and since then i did not met with random shutdowns-restarts. keep in mind this is 2 days only and it could change or miss behave at any time. after running 1-2 weeks i will report back