Difference between samsung spinpoint T & P

[elitetrick]

i dont know much about hardrives so this may seem like a stupid question to some of you but could someone briefly explain the difference between samsung spinpoint T range and samsung spinpoint P range?

is it just sizes? T seem to be bigger than P? any performance difference?
as ill be buying one of these drives tonight, thinking either the 250gb P or the 320gb T, which would be better?

 

[Garyj881]

Don't know the difference to be honest but id get THIS for a few ££ more with 16mb cache