Currently I have two 128 Mb DIMMs of NEC Virtual Channel PC133 CL3 RAM - I just bought 256 Mb of more RAM (A single 256 Mb DIMM of Atlas Precision PC133 RAM). When I combine both in my mobo, it only recognizes my 2 DIMMS of NEC Ram (No matter what order I put the RAM in the slots of the Mobo). If I take the NEC RAM out and put just the Atlas RAM in, it works fine - so the RAM isn't faulty. It's just when I combine the two, the new Atlas brand RAM I bought does not work - it isn't recognized. My motherboard supports up to 512 Mb of RAM, so does anyone know possibly why the two RAM DIMMs can't be combined. Both are PC133, so I would have figured it would work fine.