1DPC vs 2DPC

1DPC means one DIMM per memory channel. 2DPC means two. The second DIMM adds capacity on the same channel, and the board may rate a lower memory speed to run it. Spec sheets list the two separately, as in AMD's "Up to Max DDR5 MT/s (1DPC)" column.

AMD's EPYC 9005 datasheet rates every listed model at 12 channels and 6,400 MT/s at 1DPC. Supermicro's X14SBGM, a single-socket Xeon 6700 board with 8 channels and 16 slots, lists 1 TB at 6,400 MT/s at 1DPC and 2 TB at 5,200 MT/s at 2DPC, a drop of about 19 percent. Supermicro's H14SST-G, an EPYC 9005 board with 16 slots, lists 2 TB at 5,200 MT/s at 1DPC and 4 TB at 4,400 MT/s at 2DPC with 1R RDIMMs, or 4,000 MT/s with 2R. The 12-slot H14SHM lists 3 TB at 6,400 MT/s at 1DPC.

Populate every channel at 1DPC first. Move to 2DPC only when the capacity target needs it, and read the speed from the board's 2DPC line, not the processor headline. AMD's EPYC 9004 guide bars mixing 3DS and non-3DS modules in a 2DPC system.

Sources

Last verified October 30, 2026.