I'm using a 27" iMac (i7, 8GB RAM) at work and normally run two or three virtual machines at the same time, which hurts the performance of each virtual machine.
I've learned on these forums the best way to increase virtual machine performance (aside from RAM) is to have them running on a separate hard drive from the one the OS is on. Of course with the iMac you can only have one hard drive and not even an SAS or solid state drive (well you could probably take it apart and put one in yourself but I wouldn't be permitted to do that).
That being said, do you think it would help to run one or more virtual machines from a firewire external drive (or a usb 2.0)?
Thanks for your input!