Yes, they were drastically different. Xerox built their own systems. Look up the Dolphin and Alto, they were basically minicomputer-class systems with custom CPUs built out of 74 series and bitslice components, no single-chip microprocessor. And very expensive.
It wasn't until the mid to late 80s that microprocessor systems built around the 68k series were able to run Smalltalk 80 well. And that was with Tektronix and others spending thousands of man hours developing techniques to implement the VM well. And many of those systems were still basically dedicated to Smalltalk and cost a fortune.
It wasn't until the mid to late 80s that microprocessor systems built around the 68k series were able to run Smalltalk 80 well. And that was with Tektronix and others spending thousands of man hours developing techniques to implement the VM well. And many of those systems were still basically dedicated to Smalltalk and cost a fortune.