Guys I have a very strange problem that I can't explain. Our home file server is a Dell Precision 390 it runs a Perc 5i I have two virtual raid 5 disk groups created. The first disk group is all Samsung 2TB drives and the second disk group is Seagate 500 gigs drives. The first raid 5 has 5 hard drives so it takes up all 4 connections on the first slot and uses one connection on the second slot. I have network shares created on both groups if I copy data to both virtual disk groups the server crashes and reboots. If I disable use BBU everything works fine since I'm turning off the cache. Now I have already tried 2 different perc 5i controllers I've ran a diag on the battery and the levels are good. I even went as far as pulling this card and hooking everything up to another system that I have with Windows 7 on it and needless to say it performed great no crashes. So I than reconnect everything up to the Precision I forgot to connect power to one of the drives and the array came up in a degraded state with the controller running a rebuild on the drive I forgot to plug in. Now here is where it gets strange during the rebuild I decided to copy data to both virtual disk groups and it worked fine. So I just ran another test copying to both disk groups and the server is crashing again I am running Windows Server 2012 which has built in driver support for the Perc 5i. Also one other side note if offline any one of the drives hooked to the first disk group which is all Samsung's everything works fine. So guys I am at a complete lost please advise.