InDesign CS5 (7.0.4) on iMac 2.7i5, 12GB RAM, OS 10.7.3 runs very slowly when editing tables, applying cell styles and table styles. Almost hangs - no spinning beach ball. This has only been happening for the last few weeks, and also happens on a MacPro (Also 10.7.3), 2 x 2.26 Xeon & 12GB RAM. Have tried SING removal, but makes no difference.
I'm guessing John, or resident expert on these things, will want to see it, so please when it hangs, run Activity Monitor, select InDesign, and run Sample Process. You'll get a report. Upload it to http://pastebin.com/.
If it were an actual hang, he'd want you to do more, but we'll wait and see what he says.
Yup, Peter is spot on.
This sort of thing can be tricky though...not quite slow enough to be easy to measure?
What kind of document is it? Hundreds of pages? Cross-references? Part of a book?
Have you tried exporting to IDML and re-opening? Does the slowness persist?