fc5 firefox 99% cpu against helper applications

[Skunk Worx]

When the FF downloads.rdf file gets large, FF gets kind of evil on my box.

Usually located somewhere like :

.mozilla/firefox/ky24i2u2.default/downloads.rdf

Mine was 1/2 meg. and firefox would spin 99% cpu trying to start 
downloading helper app related links--realplayer, hxplay, mplayer, etc. 
Basically FF locks for 20-30 seconds.

Not every time, but usually the first attempt yields a 4-5 seconds lock, 
then additional tries of the same download exhibit the 20-30 second lock.

Clearing downloads makes the problem go away...helper app startup is 
very fast every time.

Do you think this is worthy of a bugzilla entry? Anyone else have a big one?

---
John