Virtual PC Performance Issue

Recently Installed VPC onto Windows 7 Professional with XP Pro SP2 as the guest O/S

Have ensured that all the optimization recommendations suggested by MS and Ben's VPC weblog have been implemented.

When I am only running XP within the VPC it is very, very clunky. Mouse movements are jerky, scrolling text is also very hit and miss. BUT, if I start a disk intensive process in the Windows 7 host, such as Windows defender full scan, the VPC and XP flies like the wind. So, at the moment I am having to start the full scan every half hour or so to ensure I can work within XP.

Anyone have any suggestions as to why this is and whether I can ensure XP runs as well as it obviously can?

Thanks in advance.

oops

Found the thread below which suggests the <enable_idle_thread> addition to the Options.xml file...

It now flies :)