My 2GHZ 3GIG Core2DUO MINI running Leopard smokes my workstation (Dell 3.06 GHZ with 3GIG mem Core2DUO (running XP Pro with SP3).I find that surprising, Audiofun. Is your Dell running an as delivered software configuration replete with bloatware, or have you installed/reinstalled the software yourself? How many background processes does Task Manager indicate are running? Are you using a Norton/Symantec security suite or other security software that is commonly reported as leading to instability and/or slow performance? Do you defragment the hard drive periodically?
My XP Home SP3 installations (installed from scratch by me) have only 25 to 30 background processes running, even though I have a LOT of software installed (upwards of 70 programs). These systems all fly.
That includes even a 6 year old Pentium 4/Asus P4C800 system, as well as two systems I've built more recently that are more powerful than your Dell (E8400 and E8500 Core2Duo's overclocked to 3.8GHz on Gigabyte X48 and EX38 motherboards). All three systems have 4gB RAM and Western Digital 10,000 rpm Raptor hard drives as system drives.
Regards,
-- Al