Mix and Match DDR3 RDIMMs with Xeon E5?

[DolphinsDan]

Here's my situation.

I have 8 DDR3L RDIMMs and 16 4GB DDR3L RDIMMs.

I have a motherboard with 24 DIMM slots.

Can I do 8GB in 4 slots per CPU then 8x 4GB in the remaining slots? Or do all have to be the same size? So like 8 4 4 8 4 4 CPU 4 4 8 4 4 8

What about if I did 8 4 8 4 CPU 4 8 4 8?

 

[Dev_Mgr]

You'd really want to check with the motherboard manufacturer (manual), but usually these are the typical rules with Intel processors:
- 4 ranks max per channel (so if your 8GBs are dual ranked, the 4GBs would have to be single rank each (if these are dual rank, you can only do 8+4 per channel)) -> ranking is usually in the description on the dimm and designated something like "2R" for dual rank
- each memory channel needs to have the same memory population, unless you don't put anything in a channel