смотрим спеку:
http://www-03.ibm.com/systems/x/hardware/tower/x3200m3/index.html

написано:
Up to 32 GB memory, with DDR-3 ECC memory, up to 1333 MHz; 1 GB, 2 GB and 4 GB UDIMMs; 1 GB, 2 GB, 4 GB and 8 GB RDIMMs

подходят либо анбуфферед диммы, либо регистеред диммы, с контролем четности ддр3, соотвественно регистровые с небуферизированными путать в одном сервере нельзя, либо те, либо эти.

о чем собственно аглицким по белому написано в даташите:
http://public.dhe.ibm.com/common/ssi/ecm/en/xso03082usen/XSO03082USEN.PDF

пдф-ка из ссылки вышеThe x3200 M3 ships with either one or two DIMMs installed and supports up to 32GB of
Registered DIMM (RDIMM) memory in 6 DIMM sockets, or up to 16GB of Unbuffered DIMM
(UDIMM) memory in 4 sockets. It uses PC3-10600 or PC3-8500R-777 double data rate III
(DDR3) memory (operating at 800, 1066, or 1333MHz. depending on the processor type and
memory configuration) for faster access, and provides ECC memory protection.
The x3200 M3 supports either 1, 2, or 4 UDIMMs, or 1, 2, 4 or 6 RDIMMs. Valid
configurations include:
• UDIMMs in Slot 1 only, or Slots 1 and 4, or Slots 1, 2, 4, and 5. (16GB maximum)
• RDIMMs in Slot 1 only, or Slots 1 and 4, or Slots 1, 2, 4, and 5, or all 6 slots. (32GB
maximum)
UDIMMs are available in kits consisting of one 1GB DIMM or two 1GB, 2GB, or 4GB
DIMMs. RDIMMs are available in kits consisting of one 1GB DIMM or two 1GB, 2GB, 4GB,
or 8GB DIMMs. Mixing UDIMMs and RDIMMs in the same server is not supported. Mixing
ECC and non-ECC UDIMMs is supported; however the result will be all DIMMs operating in
non-ECC mode.
The x3200 M3 supports both single- and dual-rank UDIMMs. Single-, dual-, and quad-
rank RDIMMs are supported. Up to 6 single- or dual-rank RDIMMs, or up to 4 quad-rank
RDIMMs can be used. Maximum capacities include:
• 4 single-rank UDIMMs (4 x 2GB = 8GB)
• 4 dual-rank UDIMMs (4 x 4GB = 16GB)
• 6 single-rank RDIMMs (6 x 2GB = 12GB)
• 6 dual-rank RDIMMs (6 x 4GB = 24GB)
• 4 quad-rank RDIMMs (4 x 8GB = 32GB)