Am 22.01.2014 17:55, schrieb David Sommerseth: > On 22/01/14 17:30, Yasha Karant wrote: >> We have been converted without choice to a Microsoft Exchange >> proprietary email server, although IMAP service has been retained. I >> have 64 bit X86-64 Thunderbird on my office machine, and 32 bit IA-32 >> Thunderbird on my laptop, both under SL6x (64 bit office, 32 bit >> laptop). The office machine is 4 core, my laptop is 2 core. On my >> office machine, when using the MS IMAP server, Thunderbird runs very, >> very slowly, with a single core reported load over 100 percent > [...] > > Another maybe not so related thing might be add-ons in Thunderbird. I > remember that the earlier versions of the Lightning calendar add-on > caused serious Thunderbird lags, and often making Thunderbird not > responsive when updating the calendars. I believe this issue was > particularly fixed around TB17 or so. So I'd recommend you to do > benchmarks with all add-ons disabled, if you have anything loaded. > > I too would suspect add-ons, especially lightning. Try `thunderbird -safe-mode` Regards, Florian Philipp