Substitution or simplification seems to be the name of the game. Yes, I would suspect one or more of the RAM sticks.
What I would do is to simplify the arrangement for starters. Use only one HDD, one stick of ram and only the barest of essentials (leave the RAID stuff out for the present).
If it runs sweetly after stripping, you can try the rest of the bits back again one at a time starting with adding the RAM