OK....I've actually tried this....
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional with 3GB" /noexecute=optin /fastdetect /usepmtimer /3GB
The two lines let me choose from the two options. However, if I choose the second option then it immediately crashes, i.e. before the Windows startup screen appears.
The Microsoft website seems very confused over whether /3GB switch is supported by XP Pro or not.....different pages say different things. So I'm not too sure where to go from here. Any ideas?
Cheers
Simon