I was just having a look through speccy, and noticed that my Western Digital Caviar Black 1tb is only 5400rpm with 2MB Cache, while it is supposed to be 7200rpm with 64mb cache. Here is a screen shot any ideas whats going on?
Now you know that Speccy may not have your drive properly defined in either version, so why bother with it? The issue could also be with your system that isn't 100% compatible with Speccy.
Speccy doesn't work properly with my systems (WD Black and other drives), but it doesn't bother me as I know what hardware I installed. On my systems it doesn't display the drive speed or cache size and other info isn't always accurate.