What would be a good way to tell which fonts my PC never used (or only rarely used) ?

By looking inside C:\WINDOWS\Fonts I can tell when they were last changed, not when they were last used by an application.

Also, has anyone noticed a significant performance improvement from deinstalling fonts?

It depends on how many you have installed.I have a Library of over five thousand fonts.If I installed them all I think my pc would take about 5 days to boot up!!
I normally have about 30-40 fonts installed at anytime, and my 2gig proc and 1gig RAM seems fine with that.
I have a great application called AMP Font Viwer and that is great for sorting out large libraries of fonts.you can preview al the fonts in a folder and with one click add them to the windows font folder.Also you can remove fonts very fast and also make groups of fonts within its library.

The default set would be fine. Usually fonts don't initialize until you start a program that requires that font.

xboxrulz

I have about five extra, but that was added ages ago, my Paint has started lagging hugely, taking 20 seconds to open. Would removing a few, probably some of the default, help? 384mb Ram, I normally get alone boringly ok.

Maybe you should then. Also, 384 MB is bare minimum. The industry standard is 1GB at the moment while gamers will opt for 2GB.

xboxrulz

hey mark i have amp font viewer! never use it though

i have about 800 fonts, i never intend on uninstalling them though. i need them too much.

ive never uninstalled a font to answer your question, lol

If you right click on a font file and go to properties, you can view the last accessed date. This will show you what fonts are in use. Having font files sitting on your hard drive should not cause much of a performance issue at all. The only fonts that will actually be loaded are the ones that are currently in use by some running service or application. A listing of all the fonts will be grabbed when you open the font picker in any application, but thats no different from getting a file listing in the open menu. The number of fonts installed should not affect boot up time unless you have a lot of applications set to load on boot that all use different fonts. Also, keep in mind that most font files are somewhere near 1/3 MB, so you would have to remove probably around 30+ before you could start to notice any effect, and that affect would be dramatically small. Really, removing fonts would only make a difference Once you start removing a couple hundred at least, and then only if all hundred of them are in use.

~Viz

Fonts usually don't impact too much on performance. Even if all of them were load on demand (starts when a program needs it) they probably won't take up too much memory anyways. Take this for example. If you have 500 fonts each averaging at about 100kb it would still only use 50mb of memory. Now for the average pc with 1gb of ram this is really not much of an issue, but then again no one will have a program open that needs all fonts avaliable all the time.
I have heard stuff about having too many fonts installed slows down startup, personally i find this isn't true. It might've been true on older operating systems but for xp, in my case anyway it has little if no effect on performance or startup time.

I can say that if you need the fonts go for it and install them, you will notice little difference under xp.
What i usually do though is that i don't install fonts for the hell of it, for example i've downloaded a photoshop psd file and to edit it i need a font that the author has used. This is usually the only case i install fonts, i don't need the novalty ones that you can find everywhere.

Hope it helps
-HellFire