GA-F2A88XM-DS2 (rev. 3.0) RAM Module confusion

[ANDY BROM]

Does anyone know why  Kingston KTD-PE313S/4G wont work in this board but Kingston KTD-PE313E/2G will the vendor of the ram modules i bought says they aren't on the QVL but neither are the ones that work any help welcome andy

[Tiger]

Kingston KTD-PE3138/4G 4GB 1333MHz is Registered Memory ECC.
Registered memory is used in Servers not Desktops.     
GA-F2A88XM-DS2 (rev. 3.0) doesn't support the use of Registered memory.

Kingston KTD-PE313E/2G Standard 256M X 72 ECC 1333MHz 240-pin Unbuffered DIMMDDR3, 1.5V, CL9, FBGA, Gold.
Unbuffered memory is used in Desktops.

Normally on that motherboard, memory is chosen depending on which APU or CPU you are using. The memory controller is in the CPU or APU.