I'm also having some issues with the client freezing though only for short durations, maybe 5 seconds once every 30 minutes/hour, not sure exactly. It's been happening for a while in some earlier releases than 2.16 too though I'm not sure when exactly it started.
The client will freeze even if I'm not actively doing anything in it it seems, or may freeze if I scroll the userlist scrollbar in channels, or click over to transfers, or go to write text in the chat channel text entry field. Ultimately I'm not sure that it's even these actions causing it or that the freezes just happen to occur during doing these things. All control over the client is lost during these moments, even background transfer processes halt I think, too.
I did screenshot using the Process Monitor at one point which does show the drop at least:
http://i.imgur.com/Ht6NCgu.png
Client is using 736 MB of system RAM currently - 1 active download, 134 actively seeding, 2 channels open (1 streaming).
The rest of the system seems fine during these freezes so it seems like it's Tixati-specific.