Determining bus speed/memory

[Robert Fitzpatrick]

I have a couple of servers (5.5 and 6.2) at a remote location that I
need to order additional memory. I need to know bus speed and, if
possible, how many chips currently installed to help determine whether I
need to replace or match and fill available slots. For instance, I know
one server has 1GB of mem, but do I have two 512MB or a single 1GB chip
in place now. Can someone tell me the commands to determine either of
these things?

Thanks in advance!

-- 
Robert