PC 3200 400MHz. DDR is manufactured in 2GB DIMMs? For 4 GB system memory, 4 x 1 GB equals 4 GB system memory for chipsets using DDR. If your DDR MB has only 2 DIMM slots, 2 x 1GB DDR is your max system memory. It's been a while, but I do not recall 2 GB PC 3200 DDR Dimms being available.