Not to be rude, but this question has been discussed quite a bit around these forums. Using the search function will also yield your answer faster.
Second, memory is another word for RAM; hard disk drives are usually referred to as storage, FYI.
Ok, from what I remember, there is a certain difference in speed. It's not huge, and if you were trying to decide between 100GB 5400rpm and 100GB 7200rpm I'd say that it's probably not worth the $100 premium. However, as you're gonna spend those $100 anyway, I would recommend getting the faster drive. 120GB is really not that much more than 100GB, and if you have an external drive, it's even less of a point. And if 100GB is not big enough for you; 120GB wouldn't be, either.
However, there's also noise and power consumption. The faster drive could be a bit louder and consume a little more power, and although it's probably not much, it might be a concern if you're going to be on battery a lot and want to get as much time as possible out of a single charge. In that case, I think the the slower drive would be a better choice.
Anyway, to answer your question: Get the faster drive. While the speed difference is only marginal, it is faster.
Oh, and maybe consider getting only the 100GB 5400rpm one (if we're talking about the 15" MBP, that is) and getting 2GB of RAM instead. More memory will benefit you a lot more than the slightly faster HDD.
Comments
Second, memory is another word for RAM; hard disk drives are usually referred to as storage, FYI.
Ok, from what I remember, there is a certain difference in speed. It's not huge, and if you were trying to decide between 100GB 5400rpm and 100GB 7200rpm I'd say that it's probably not worth the $100 premium. However, as you're gonna spend those $100 anyway, I would recommend getting the faster drive. 120GB is really not that much more than 100GB, and if you have an external drive, it's even less of a point. And if 100GB is not big enough for you; 120GB wouldn't be, either.
However, there's also noise and power consumption. The faster drive could be a bit louder and consume a little more power, and although it's probably not much, it might be a concern if you're going to be on battery a lot and want to get as much time as possible out of a single charge. In that case, I think the the slower drive would be a better choice.
Anyway, to answer your question: Get the faster drive. While the speed difference is only marginal, it is faster.
Oh, and maybe consider getting only the 100GB 5400rpm one (if we're talking about the 15" MBP, that is) and getting 2GB of RAM instead. More memory will benefit you a lot more than the slightly faster HDD.
I am about to get a 17" MBP. I think I'll opt for the 120GB 5400 RPM drive. If it was 4200RPM vs 7200RPM I'd go for the faster drive.
On the other hand, an extra 20GB of memory is always appreciated. Especially after a year or so.
If they were charging a premium I wish they would have given us the option for a 160GB HD.