Do I have realistic expectations (Recording with FRAPs)
 

I thought I'd be fine recording with my PC but today I tried recording and after about 3-4 minutes of recording my FPS would plummet to an unplayable level (from 30-40 to 1-5)

my specs:

AMD X2 6000+
Nvidia 7600 GT (256 MB)
2 GB RAM

I usually play with almost everything max at 1280x1024 resolution, when I recorded I put everything at medium-ish and tried recording at half screen at 25 FPS. Like I said, it would record fine for about 3 minutes then my FPS just completely drops and I'm not sure why. Any ideas on what I can do to actually be able to record my videos?

All I can say is this....
Fraps is a memory HOG!!!
The longer you record, the more it sucks out. At higher Res? Its even more massive!

So can I just not record? Like this just doesn't make sense to me. I can record different clips and my FPS stays around 20-30 which is playable, but then all of the sudden it will just drop to 1-10 and I have to stop recording. Even if I try to record a new clip it starts lagging horribly.

I know my PC isn't the best, but I thought that I would easily be able to record while playing WoW, its not like WoW is the most demanding game out there. Does this sound like normal performance to you other movie makers?

Is it vista? :f

Nope, running XP.

Yes, actually it does sound realistic. Fraps was designed to give optimum performance to your gameply while recording. Not the opposite.
I would suggest changing your resolution 1024X768 go to a size down on your FPS and run Half screen. If you have sound enabled, unless you have to have it, click that off.

256mb graphics card is your bottle neck, I had similar problems with an AGP radeon 9800pro :D. Consider upgrading if you wish to follow your movie making dreams! (you can pick up a 8800Nvidia for around £50 these days, not sure on the euro conversion)