While looking for some info on some vague term my cousin asked me about, I found this little program called Game Booster.
http://www.iobit.com/gamebooster.html
The program can switch your PC to "gaming mode" and back. As of now, I gave it a very quick run with Unreal Tournament 3 and saw a good increase in performance.
So, anyone here ever tried the program? Tell me about your experiences with it or other similar programs.

So it just shuts down your least important services and background apps for gaming? That's usually how it works.

Interesting find. If it works as advertised, it might mean I don't really have to do any "power tweaking" to my system anymore. I usually disable a ton of services and background apps by default, but it does cost me some functionality at times. It would be nice to have an app that can do that kind of stuff on demand.
After using it a bit, that's exactly what it does. By default it seems to pick on the obvious Windows services, like automatic updates, secondary logon, error reporting service, etc. and disables them, but it also scans for additional apps you have running and suggests disabling them. For example, on my system it found the Java Update Service (which I didn't even realize was running), Lightscribe Control Panel, Logitech SetPoint and a component of my anti-virus software. My system was already partially customized on running services, so it only managed to free up about 50 MB of RAM, but on systems with Windows default configuration it appears it could easily find a lot more to free up.
This is a pretty handy app to have, definitely worth a try. Thanks for pointing it out Falci!

This'll be a good tool for troubleshooting my sisters PC, I can kill all the crap she's got running on it and show her that a computer that not overloaded with useless shit will run a bit better

I might test this out to see if it really does what it says, but usually with these things, I never really see any increase in performance.

Same. Usually these things end up screwing my PC too. I'm very wary of it, can anyone else confirm it's reliability?

While I haven't tried this particular program, I can tell you from experience that this probably won't do anything tangible and might actually decrease system stability. Additionally, from Vista onwards many of the tweaks this program probably does won't actually make a difference due to the reworked handling of things like services. If you want your system to be faster try things like disabling background applications via msconfig, doing regular defrags (if you have XP), and setting security programs to monitor less aggressively; this will give you a performance boost all the time, not just when you are running games.

Tried it and liked it. Thanks for the link. :)

As some here have already mentioned, it just does that annoying job of shutting down things for you. And turning them back on after you're finished. It makes the process easy and simple.
When I first bought UT3 it would run smoothly. Ever since I registered it on Steam, it became basically unplayable. I could turn down a lot of graphical stuff, but since it worked before I firmly wanted to manage to get it working properly again.
Of course, my PC became overloaded with lot's of stuff in the last months, many which I can't quite get rid of yet, so Steam isn't the only one to blame. Cutting things short, this program allows me to get back some of that performance without much effort. But I'm still to do a long and decent test on it.
Good to know you guys are enjoying it. :D

Interesting... I don't really trust this stuff, usually because I keep my gaming system pretty sterile from craplets and such, but I think I'll try it out to weed out Vista's services.

I'm defiantly going to give this a go on my fiancée's machine, she's a big Sims 2 fan but the amount of extra content they put into those expansions make it run like treacle going uphill in snow-storm. I'll report back if there is any improvements.

I thought Sims 2 had pretty low requirements anyway.

She has an old computer, its a 32bit thing with only a 2ghz rated processor (Its one of those AMD ones).

Gotcha.

Yep, I was thinking of upgrading it to a hamster wheel. I heard you get more cycles per minute.