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 -- and > does not appear to be using more than one core. On my laptop, > Thunderbird has acceptable performance, and typically shows a load of 10 > percent. Office LAN is IEEE 802.3 at 100 Mbit/sec; home is over IEEE > 802.11 through a DSL box from the telephone common carrier. > > Anyone else having a similar experience? Is 64 bit Tbird significantly > different from 32 bit Tbird? I haven't done any benchmarks, but the difference between the 32 and 64 bit should mostly be in addressing. That itself shouldn't be much noticeable. But I do recognise your issues with a sluggish Thunderbird. When my employer moved my IMAP account many years ago from a server in Europe (where I'm located) to a data center in the US, Thunderbird got noticeably slower (IMAP access is only available via the in-house networking, not publicly on the Internet - so capacity of the VPN concentrators most likely caused longer network delays). I solved that by using offlineimap + dovecot IMAP server locally. That made my Thunderbird really fast again. So I presume it got something to do with the networking code in Linux. But the plus side here is that I don't have to do any hassles with "offline mode" in Thunderbird, and I have all mails available locally - in all programs supporting IMAP, even without network access. 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. -- kind regards, David Sommerseth