Actually Spock is right on the dot.
One thing to always remember is that the download is as fast as the weakest link in the chain, meaning this:
1- your computer
2. the line (Internet connection)
3- the server your getting your downloads from.
Now for easy writing I'm starting backwards so bare with me here
The server in question probably is fast enough, so not to worry there, and if it isn't then there is not much you can do about that one either. You wrote in your post that you have an fast Internet connection, so lets go with that as in being k too shall we?
Now your computer:
And you thought correctly. The more memory, the more available for a memory buffer, therefore the faster a video or sound file will be able to play. The real problem is, how fast can your computer download the file and place it into the buffer.
Lets take a deeper look into this statement:
If he has a 10 gig Hard drive and is using a Windows determined Page file, also called Swap file then it works as follows:
Lets assume for easy thinking here that from the 10 gig he has 1 gig Swap file, for speed its nice to have a separate partition just for the Swap file alone, but on a 10 Hard drive thats obviously not an option
So here we go:
Server with the file ------> Internet connection ----> computer.
translates into speed like this:
Fast enough server ---> fast enough Internet connection ---> 500 MHz cpu (central processor unit) + Ram +/- 400 MB ---> 1 gig Swap file
The weakest links in here are both the Processor as the Hard drive, and then maybe the amount of Ram.
I will try to explain why:
Your computer significantly slows down if the Hard drive is not big enough. (read filled up with data) and 10 gig total isn't much, lets put it this way, its a Windows thing, not your fault
Windows does more btw, it uses +/- 250 MB Ram for itself, so your left with 150 Ram to play with or multi task or whatever. (assuming you are running Windows XP here)
The workaround for this problem is the Page file, so what happens is this:
You are trying to download a movie file with 150 MB ram, using a 500 MHz processor on a maybe full Hard drive, so windows first writes it down to the page file, which act's like a temporary file, read buffering, when the Page file is full it starts to "use" the left over Ram and you will either get the error msg you got before or notice the slowdown you are talking about.
I hope this bit of information makes some sense, so you maybe have a clearer idea what your computer does.
And no i did not make that smilie