I think university students should definitely start with older processors, and then gradually change the levels. I agree there is an architectural change in the newer processors, plus the additional cores. But, working with an older processor with limited memory and processing ensures the programmer realizes how important is each line of code and appreciates the comfort provided by newer processors and thus their complexity.
The first computer I programmed was a Z80 micro-controller connected to some basic peripherals (LED readout, sensors, actuators, stepper motors, potentiometers, etc...). There was no compiler, no assembler; nothing but a keypad to enter the instructions into memory and a button to start execution.
The CPU was less powerful than any of the x86 32bit chips that were widely available at the time, but as a kid it still really gave me the idea that whatever I could think of, I could make a computer do.
I'd agree, understanding things at a really basic level first helped me to better understand things at a higher level later on. It probably helps me to keep in mind what a computer actually needs to do to run code as well. I think it's probably one of the reasons Knuth uses MIX in TAOCP.
