I run Vista Ultimate on a Dimension XPS at home. As good as the machine was 3 years ago when I got it, 1 Gig of RAM is just not cutting it anymore. With another Gig still costing over a $100, I decided to try the poor man's solution. I went out and got a $20 1Gig USB memory stick and plugged it into the PC.
Vista includes a feature called ReadyBoost. There have been plenty of posts about it, but I wanted to point out that it really does work. I was doing some tinkering with the XNA Framework (more on that later) and having a couple of Visual Studio Express instances running along with 3D Studio MAX instance and an IE window or 2 (or 5) was taking its tall on the system.
With the memory stick in and configured to be used for ReadyBoost, the system is SIGNIFICANTLY more responsive. Switching between windows is now practically instantaneous and launching a new IE window doesn't take a good portion of 30 seconds anymore. Another noticable thing is the responsiveness of the system when I sit back down in front of it after not suing it for a day. It's common for the computer to "wake up" for a few minutes when this happens, but ReadyBoost (which is essentially a cache for the swap file) makes that a non-issue.
Eventually I will add another Gig of RAM to that box which will probably reduce the effectiveness of the ReadyBoost cache. It would be interesting to see how much the extra RAM will help vs. ReadyBoost...
Couple of notes about ReadyBoost:
Overall: ReadyBoost rocks and, unless you have 2+ Gigs of RAM, it is totally worth it.
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.