What are the model numbers for each capacity?
Here you go!
500GB - STGS500401
250GB - STGS250401
Bought the 500 GB drive last time. If you have a USB to SATA adapter, Seagate has free cloning software that you can download and run to make a clone of your crappy physical drive and be basking in the wonders of SSD. Computer start up on Win7 went from 3-5 minutes to less than a minute.