I droped back to version 2.4.3 and now my files are being indexed immediately again and performance is acceptable after the indexing procedure, which is just a minute or so for almost 4000 mp3's. I'm sticking with this version until one of the new ones will run flawlessly on my G4 400mhz 512 MB ram. Hell I'll even pay for it if they could only release a version that works as supposed to. No money from me yet because if I register they'd just give me the 2.5.3 version and that one isn't worth using. Takes hours to index my mp3 collection and when I quit it doesn't remember the indexing process, and the uninstaller always quits and won't uninstall.
I guess I'm saying that with each new release the worse the application becomes.

LimeWire is hashing your files so files can be identified by a more secure attribute than just name and size. It's used to eliminate corrupt files and fakes in the gnutella network. I know it takes several hours to index lots of mp3s, but LimeWire will not index your mp3 collection twice, - unless you move, edit or rename your mp3s. You should get used to hashing since all future versions will have it. It may even be possible.

Version 2.4 will probably not be able to download popular files from LimeWire (beginning with 2.6), BearShare (4.0.2+), Shareaza (1.5+) and all other clients that implement upload queueing, so I'd not hang on to 2.4.3 if I were you.