Dell PowerEdge R730xd — Full Technical Specifications

The bay row is longer than on any other page in this generation, and each option within it is a physically different chassis; that row, not the processor one, is what you are really choosing between. Note the line stating that accelerators are unsupported — it is there because the mid-bay and the cards want the same volume, and any listing elsewhere promising both is describing a machine that was never built. The express-flash line applies to one backplane only, which is the sort of qualification worth reading twice before an order goes in. Matched intake matters more here than elsewhere: a storage cluster drawn from one batch behaves better than one assembled from four.