Re: How accurate is Fraps fps rating?
It is pretty accurate. Keep in mind that because it is polling data, you might have a +/- discrepency but it is relatively accurate.
Typically you might not notice a drop to ~15fps or so that much unless you are in a fire fight and moving around at more than a crawl. BF2 does not take advantage of your 2nd core either so dual-core would not assist.. What I would suggest is to set affinity to your second core for FRAPS so it reduces any extra drops you might be experiencing.
I can notice clearly while playing cs:s and having extra choke on some servers absolutely kills frame-rate and it drops from 100-150 down to about 15-20 and I can tell very clearly.
If you are running around and still don't notice a drop in frame-rate, perhaps you really are getting a mis-reading.