I've got several of iomega's NAS boxes from their ix product line. I was looking over the specs on the current "cloud edition" models to see what new "awesomesauce" was baked into the new firmware (hence making it a "personal cloud" device) and noticed that the hardware also underwent some quiet revisions. The ix2 is still shipping with 2 spindles and 256MB RAM, but the CPU has been updated from the old 200MHz ARM to a much-improved (but unnamed) 1GHz processor. The other models were similarly updated, with the ix4 getting a 1.2GHz CPU and the stellar ix12 getting an Intel E8400 (3GHz dual-core).
In general, it means the -200 and -300 designations no longer indicate the CPU speed as it did with their predecessors, the non-cloud editions.
I've discovered that I've been in error in asserting that the older models (i.e., "non cloud") were 200MHz ARM units. Like the new units, the old ones are based on the Marvell Kirkwood ARM-compatible system-on-chip parts, which run at 1 or 1.2 GHz. I don't have enough data on the innards of the ix12 (old vs new), but I'm completely wrong on the ix2 & ix4...