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