Version:            (using KDE Devel)
Installed from:    Compiled sources
Compiler:          gcc 3.3.1 
OS:          Linux

When using KMail with two disconnected IMAP accounts, even when setting the account to test for email every 15 minutes, the system becomes heavily loaded after a while:
KMail uses upto 35% of memory.
While the CPU usage is low (5 - 15 %), the load average is very high - upto 7.00 or 8.00 (!!).
Kmail freezes from time to time when checking email or downloading attachments (on demand), but other applications behave normally (considering the heavy load).

Closing KMail takes about 1 minute between the main window closing and when the "cleaning mail" dialog box appears, and then another half a minute until the process shutsdown completly.

after closing kmail everything returns to normal. using both accounts under normal imap produces normal behavior, memory usage is less then 10% and the system load and response times are normal.

System: P4 1.5GHz, 256MB Memory, 512MB Swap, kernel 2.4.21, Mandrake 9.1 with a lot of cooker updates. using KDE 3.2 as the main desktop