Different guest here - running x64 Ubuntu 10.10 on AMD dual core with 4 gb ram and 2.5 gb swap. After about 30 mins Amule starts using all avaliable ram and swap until the system crashes or I have to force a reset. Run a Nvidia 7950 card on an AMD motherboard (inbuilt raedon graphics) so no intel chips to confuse the issues. I am not to sure what is causing it but it certainly a memory issue.