Quote from Macworld latest speed tests "The new 27-inch iMacs are available in two standard configurations. Both have 8GB of RAM and feature Intel’s quad core Ivy Bridge processors. The $1999 model sports a 3.2GHz Core i5, while the $1799 model uses a 2.9GHz Core i5.
Both iMacs include 7200-rpm, 1TB SATA-3 hard drives, but the drives in these two iMacs we received are not identical—and neither were their performance scores. Our $1999 iMac has a Western Digital WD10EALX Caviar Blue drive with 32MB of cache. Our $1799 iMac has a Seagate Barracuda ST1000DM003 hard drive with 64MB of cache—twice the cache of the WD, and the advantage of the larger cache is evident in our test results."
Seems strange that Apple puts the faster drive in the lower priced option. I wonder if it's the same in all of those produced?