Help for Newbie

[quarkrad]

Re above for example: You can get drives with either a 2.5" or 3.5" form factor - will this make any difference?

[Giga]

A little I guess: 2.5" will use lesser power then a 3.5" for same capacity.
Most important: should not be external powered. Be carefull with these some only have tin casing, ruined one by putting accidentally elbow on to top, nasty grinding sound: freecom black rubbered sleeved. Could throw it in the bin.