dragonfly522 :
My understanding has been that the less RAM that is being used, the faster it accesses and delivers the data, because it takes less time to look through a small amount of data to find what you need than look through a large amount of data that would take longer to access because there is more data to look through.
That's a misconception a program doesn't search for data in memory, because it already knows where it is and retrieving something from RAM is lightning fast.
If you've been in a water park (or something similar) before, they have these big rooms with tons of lockers and once you store your street clothes in one of them you get a colored wristband with a key and a number printed on it. When you come back you simply look for the row with blue lockers and look for number 14 instead of running mindlessly through the whole room and trying the key in every lock. It's a bit more complicated but it basically works like that.
What geofelt means with 'table lookups' is something that happens within a program and has nothing to do with accessing memory. That is just about how smart the programmer was and how he organizes big amounts of data. The analogy to that is one person that has everything neatly organized with file cards and another one, who just has a ton of cards scattered over his desk. The first person will find a specific card always at the same time, while the second person is only faster if he gets lucky or has less cards to look at.
dragonfly522 :
I would imagine the same is true for the hard drive.
A hard drive works like a group of books. When a program requests a specific file, the system looks at the index to see in which book and on what page the file is. Then you only have to pick up the book and flip through the pages until you reach the right one.
That's why HDD access takes longer, because it needs to 'flip pages'. It gets even worse if the drive suffers from fragmentation, in that case you have to jump back and forth between pages and even books to retrieve every part of the file. Which takes a lot longer, because you can only look at one book and one page at the same time (while looking for only one file).
What makes HDD accesss so much slower is that the disks have to spin to that point. But HDD size doesn't really affect access times either, as manufacturers 'cheat' by changing the structure of the disks and the way they're accessed.
Conclusion: RAM size doesn't affect access times, because it already is lightning fast and it would always be worse to swap stuff back&forth on the HDD.
HDD size doesn't affect access times, because manufacturers 'cheat' and try to keep average access times as stable as possible regardless of disk size.