I'm running Shareaza 2.4.0.0. After running for a while, CPU usage for Shareaza.exe spikes at 100% and never comes back down. I have to exit Shareaza to be able to use my computer. When I start Shareaza again, it spikes to 100% CPU usage again after a few minutes.
I've got 121 files / 29.5 GB in my library, which doesn't seem excessive. It connects to Gnutella2, Gnutella, and eDonkey fine.