and finding out if your drive has an 8 MB buffer or not...
right click 'My Computer' --> 'Manage' ---> 'Device Manager'
look for your hard drive in the list to the right. do a search on the internet for the model number that is provided. you'll be able to find the specs with this information.
PW5 64, E6300@2.8, X1900XT, (5) 74GB RAPTORs, 2GB Corsair XMS800, ATI HDTV Wonder, DELL 30\"