ITunes 10.6.1 x64 regularly stops responding.

Question

Hello -
My name is Erick and I'm an ACMT/Network Engineer; Apple-certified, but not Apple-employed.
I have experienced an issue with iTunes 10.6 in general that has not been resolved by the latest update to 10.6.1. Upon opening the iTunes application, it initially responds but within 15 seconds freezes and is Not Responding. The unresponsiveness lasts up to five full minutes, then the program begins working again. The issue appears to begin as the iTunes Match cloud icon begins animating and checking for updates to my music library.
The same situation also occurs regularly if/when I make changed to a Smart Playlist. The program stops responding for up to five full minutes, then works properly.
Here's some additional information about what I've already attempted in efforts to fix the issue. Does anyone have any suggestions or recommendations for how I might remedy this issue? While it's not crippling my use of the application entirely, it does cause unexpected headaches and delays, and it'd be great to fix it.
I've attempted to resolve the issue by opening a new library and using it temporarily to test, rebuilding the library by starting fresh and importing from my iTunes Library file, and I've also attempted to use iTunes 10.6.1 from a different user account. Finally, I loaded iTunes 10.6.1 onto my external troubleshooting drive which is running the same OS. I've seen the issue persist in each situation. I've also attempted to run iTunes in 32-bit mode as I experienced some success with this fix related to other issues in the past.
I am using an iMac 27" with the quad i7, 16GB, and a 1TB hard drive. All of my music is on iTunes Match and none of it is being stored locally on this machine. My TV and Movies are being stored on an external 2TB drive, as is the iTunes Library file itself.
I would be happy to provide any logs or additional information that could help resolve this problem. I appreciate any assistance and hope to have this resolved at some point. My iMac is typically on 24/7 as it operates as a streaming server for services like StreamToMe, SugarSync, Plex, and other file services. Additionally, iTunes is typically open 24/7 to provide streaming ability to my Apple TVs (1080p versions), though I do have a scheduled task which exits and re-opens iTunes at 4:30AM to prompt syncing of my iOS devices before I head to work (putting the latest unwatched media on them).
I'm sure some of this is unnecessary or extraneous information, but I wanted to be thorough in my explanation and context. Thanks again for your assistance, everyone.

Answer 1

I have resolved my issue with iTunes' unresponsiveness and wanted to post the solution for anyone who might be experiencing similar symptoms. It was really quite simple to fix, I just didn't see it for what it was:
iTunes Match was causing iTunes to stop responding for several minutes at a time, and several times a day.
iTunes Match - which also forces Genius Mode to be on (something that used to cause my iTunes 10.5 to freeze before I turned it off) - would regularly attempt to refresh my database of 21,000 matched songs (none of which were stored on the computer - just in the cloud) and when it would attempt to update or refresh that library, the program would stop responding.
The constant queueing of iTunes Match / Genius also caused iTunes to consume a significant amount of RAM - something that was also causing issues and which I posted about in another discussion.
So, the simple solution was this: Turn iTunes Match off and iTunes quits freezing.
Now, that of course completely eliminates the usefulness of iTunes Match since the music is no longer accessible on this machine in this iTunes Library. So how to restore its usefulness without recreating the problem? Slightly more aggravating, but still working right: I created a separate, fresh new library and named it iTunes Match. When I need music, I hold option when selecting the iTunes app and select my Match Library, which has NOTHING else in it but iTunes Match. When I'm done with the music, I switch back to my 24/7 media streaming library that has my 2TB of TV Shows & Movies (and device sync relationships) in it.
It doesn't seem like iTunes Match causes freezing and RAM ballooning all by itself, it just seems like in a library that's also full of other stuff, it's the final straw that kills the performance. Split the libraries up and things seem to work really well in both.
Not a perfect solution, but until the next release of iTunes, this may be the best bet. I hope this helps someone else out there, but it at least cleared up my issue. Thanks for reading.