Arduino vs Old Computers How does an arduino microprocessor compare to some of the older computers in RAM, and computational speed? Like how does it compare to the Intel 400 or the original IBM PC. I'm interested in both the Atmega328 and the 2560. Just how much better/worse is the arduino compared to an old computer?
Similar capability in turns of processing power if you compare back 10 -20 years. 

arduino is a micrcontroller not a microprocessor.  

A good example is the pdp11 minicomputer and the ti msp430 micro controllers. They share the same instruction set (approx 90%) . Both can (or could) do realtime event handling but pdp11 was more for data processing. Though pdp11 didn't have integrated peripherals

see bottom of this page http://www.cpushack.com/CPU/cpu4.html