Dave,

Actually I will be surprised if the entry level BM T42 opens fast a
large file with multiple formulas.
Some of them were shipped initially with only 256 MB of RAM at a very
low speed compared to todays' machines.
Maybe his friend is a tech guy and added extra 512 RAM (at least), he
is disabling the recalculation feature and stopping all the inutile
processes.
Also it is good to note that sometimes a serie of production is
custmized with additional option if requested by the buyre.
So maybe they are bothe T42 Architecture but wih different somponents.
He got the entry level of T42 and the other was upgraded ... I guess.

Regards,
FG