Tony, It sounds like a dimm might be reporting bad. Can you do a quick test and swap a2 and a4 with a1 and a3 to see if the error remains with a dimm or stays where it is? Also, were these 4 dimms all order together? You didn't have existing and then add a couple to make this 4? I ask to make sure the dimms are all Rdimms and that they are all quad ranked.
Hi  I have successfully install 4 x 8Gig of memory in my Power Edge T310 (Slot 1, 2, 3 & 4), the memory is correct for the server after already checking thisout with DELL (8Gb 1066MHz Quad Rank Reg ECC x8 Module).  When the server boots I get a memory initialization warning message saying that the memory may be reduced as a result and issue. Is goes onto say that theconfiguration is invalid and gives warning for A2 & A4 When I run the server unified set-up memory diagnistics it passes all checks. Thediags can see all 32Gig but it reports that the BIOS can only see 16Gig. I have updated the server BIOS to 1.8.2 the latest version that I can find on theDell website. I have reviewed the hardware manual and everything is set up correctly, I haverotated the memory to ensure that all the memory works and it does. Finally I reviewed in Windows control panel and it reports 32 GB install (16 GB usable). This sounds like a configuration issue to me, has anyone come across this before andhow did you get around it. Thanks in advance  Tony.  
Not able to access full 32Gig of Memory in PowerEdge T310