I installed DesktopBSD 1.7 ie. FreeBSD 7.2 on my test machine.

Celeron 1.1 Ghz
384MB Ram

My test case:
Copy two 6GB files to the Desktop from my home directory. Copy not move!
I launched two Konsole shells. Interestingly, the system was still responsive.

The last time I tested FreeBSD was with version 6.0. Before that version 4.3. DesktopBSD is a great product.