Okay, this may be a silly question, but you are just using a single processor, right? And you're putting one DIMM in each of the three blue slots on the back right-hand side, not the middle-front?
Those assumptions are correct.
I checked the TPS at http://www.intel.com/support/motherboards/server/s5520sc/sb/CS-030231.htm - the memory subsection doesn't mention anything about that configuration not working.
What's the part number and DRAM info? I know sometimes manufacturers change the DRAM but keep the same SKU, which leads to unpredictable behavior.
I've been ripping my hair out trying to build configs, between Intel's Configurator, and info and Kingston's back and forth, finally found some very specific details that aren't on every list:
If you use QR (Quad Ranked) modules, you can only populate 2 of the slots, not all 3, (ran into this trying to figure out config for a S3420GP, but the 55xx are the same), so when they say 2xUDIMM or 3xRDIMM it is true but only for Single and Dual Rank, if you go to Quad Rank Modules, you can only populate 2 of the slots in a set of 3.
Ok, here is a clarification, since I finally found a source that explained it in more understandable terms:
You have 3 channels per Processor, but you can only address up to 8 Ranks per channel, thus 2x QR DIMM == 8 Ranks == FULL
This is why when you go Quad rank you run at 1066 with 1 per channel and 800 with 2 per channel.
I will need to double check but I think I am using the KVR1066D3D4R7S/4G Dual rank. Are you saying that I need to install the RAM in multiples of 2?
This RAM is dual rank -
The system sees 12GB but as I said the DIMM 3 error light is on and it beeps 3 times when I start it up.
I checked the tested memory list at http://serverconfigurator.intel.com/configure-memory.aspx?id=MTY2NiMxLDI1MjAjMSwyNjExIzIsMjUzMiMx
The only tested 4GB Kingston memory is all Quad-rank:
No for Dual Rank 3DPC is allowed, (per the specs) since they are Registered, and only Dual Rank, you're only using 6 Ranks with 3 Installed. If the problem remains on the one slot, even if you swap modules, that may not be a memory issue, but I would be unsure where to go troubleshooting wise, since the memory controller in on the processor, that could be a processor or a board issue (or without knowing more, power supply even since that third dimm is an additional power draw).
OK I'm not sure if this helps but from within Windows 7 & Vista the sytem properties show 12.0 GB (7.93 GB Usable). How can it 'see' 12 but only use 7.93?
According to the configurator the KVR1333D3D4R9SK3/12G is dual rank and is compatible. I have contacted Kingston re this problem - I will keep you all posted.
I have tried a variety of validated mdules and no matter what I use DIMM_C1 and DIMM_C2 come up as failed.
I have looked at the RMM3 Event log and see the following:
673 11/13/2009 18:54:41 Mmry ECC Sensor Memory Uncorrectable ECC - Asserted
672 11/13/2009 18:54:41 Mmry ECC Sensor Memory Uncorrectable ECC - Asserted
Any ideas people???