I can confirm this problem with Jaunty but only for XP. 32 and 64 Bit Vista and Ubuntu 8.10 working fine without high cpu usage.
Linux uber 2.6.28-11-generic #36-Ubuntu SMP Fri Mar 20 19:51:24 UTC 2009 x86_64 GNU/Linux
I can confirm this problem with Jaunty but only for XP. 32 and 64 Bit Vista and Ubuntu 8.10 working fine without high cpu usage.
Linux uber 2.6.28-11-generic #36-Ubuntu SMP Fri Mar 20 19:51:24 UTC 2009 x86_64 GNU/Linux