I've got a couple of Dell workstations. One is getting replaced and the plan is to pilfer the memory from one and put into the other. Both are the same speed etc Rambus but one has 2, 256 bars and the other has 2, 512 bars. Can I remove the two dummy bars and combine the two different pairs to get 1.5 or does Rambus require the same size bars in the 4 slots?