iTunes extremely slow

Whenever I try to open iTunes the program starts gathering information for iTunes Match and the program slows down incredibly.

I tried to open iTunes while offline, but to no avail: whenever I open a file, the program keeps running for at least 30 seconds before playing the file.

If I access iTunes from my iPad, all is smooth.

Can anyone help me?

Thanks in advance.

I'm using iTunes 10.6.1 running on OS X 10.7.4.