C2SEA will not start with 4 RAM

I recently went Supermicro. I purchased a SC732-500 case installed a C2SEA MB (current BIOS version) with a Q8400 and (4x) 2Gb of approved memory (Hynix HMT125U6BFR8C-H9 ON).

All ran well for almost two weeks. Yesterday on restart, it beeps once, all the leds flash sequentially, the fans spin and it shuts down to repeat the process again in 2 seconds or so. This continues until I unplug it (no switch on PSU.)

In checking the memory I have two matched pairs of memory. Each matched pair installed in the 1-2 "A" and 1-2 "B" marked dimm sockets.

Long story short, I pulled the last stick (2-B) and it started normally. Swapping around the stick pairs, I discovered that no combination of memory install allows all four memory sticks at once. It will only start with three sticks. (And two sticks.)

(A couple weeks ago, when I built this machine, it started and restarted many times with all four sticks in the board.)

Does RAM memory (on Supermicro MB) have to be a matched set of four (4) sticks or are matched pairs, properly mated okay? (Is a Supermicro MB fussy about this?)

 

I had posted this question to Supermicro support recently and having not receive an answer, I then decided to post the question here.

Well, Supermicro support just answered and indicated that the specification are for a matched set of 4 RAM sticks.

So, this question is solved.