At Micro Center I performed an entirely un-scientific test and weighed WD1003FZEX and WD5003AZEX bulk-packed drives in my hands and they appeared to be the same weight. I wonder if they use the same number of platters, with the WD5003AZEX either having one less head assembly or being short-stroked (if that’s the correct term for a drive which only uses part of a platter). I’m sure someone at WDC knows, but does anyone here know how many platters are in both drives?
UPDATE: I think I answered my own question. By surfing around, I found that they both use a 1TB platter, so the 500GB version would only have heads on one side, which would explain why they weigh close to the same.