Mythbuntu Box Upgrade?

[Joshua Lutes]

Hay guys.

I am running Mythbuntu 8.04 on a dell tower I got from a BYU surplus
sale a year and a half ago.  It uses the PVR-350 and everything is
pretty pleasing.  The only thing that isn't so great is the streaming
media from online sources has pretty choppy video.  I suspect it may
be on account of the computer never being intended to watch online
video and its being something like six years old.  Maybe.

Anyway, I was hoping for suggestions as to what I might be able to
upgrade for the hardware in order to improve the performance so that I
might be able to get rid of the stuttering video problem.  I always
been told that increasing the RAM is the cheapest and best way to bulk
up a computer, and I guess I could do that.  Any other ideas?

This is what I've got:
512 MB RAM
1.70 GHz Pentium 4 Processor
40 GB Hard Drive
PVR-350 Tuner Card

Thanks.

Joshua Lutes