How important is to look for matching DCM?

[fzabkar]

FYI, there was a thread at Tom's Hardware where a 500GB WD drive benchmarked like a shortstroked 750GB drive with the same areal density. It appears that WD may have taken a higher capacity drive from the same generation, with two 500GB platters and 3 heads, and then reduced its capacity by shortstroking it.