T710 memory config

Hi,

Apologies about this as I know this has been discussed millions of times. I have a T710 with 12Gb of ram running in Optimixed mode. I purchased another 12Gb which matches the existing RAM from Crucial (single rank 2Gb PC3-1333) but I am struggling to get it to show up or the server to boot sometimes.

The existing memory is in 1-4-7 on both banks of dimms (I have 2 CPUS)

I tried 2-5-8 no show.

I just upgrade the bios to 6.4.0 too

Can someone offer advise on which config I should use with my RAM.

Currently I am getting mem error on boot as slots 1-4-7 aren't available in advance eec mode.

In addition to this the config in the openmanage software shows

Memory Operating Mode Configuration Optimizer

DIMM_A1 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_A2 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_A3 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_A4 [Not Occupied]
DIMM_A5 [Not Occupied]
DIMM_A6 [Not Occupied]
DIMM_A7 [Not Occupied]
DIMM_A8 [Not Occupied]
DIMM_A9 [Not Occupied]
DIMM_B1 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_B2 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_B3 DDR3 - Synchronous Unregistered (Unbuffered) 2048 MB
DIMM_B4 [Not Occupied]
DIMM_B5 [Not Occupied]
DIMM_B6 [Not Occupied]
DIMM_B7 [Not Occupied]
DIMM_B8 [Not Occupied]
DIMM_B9 [Not Occupied]

The RAM I purchased is Crucial CT2704708 6GB kit (2GBx3), 240-pin DIMM Upgrade for a Dell PowerEdge T710 System Have I made a booboo??