If you compared the 3640 using low-level Lisp benchmarks, it was comparable to other similar expensive machines at that time. The difference was mainly that it

If you compared the 3640 using low-level Lisp benchmarks, it was comparable to other similar expensive machines at that time. The difference was mainly that it allowed you to write large Lisp programs inside a large Lisp IDE on top of a Lisp operating system. Unix-based Common Lisp IDEs were just appearing or about to appear in 1986 and large Lisps under Unix was still a challenge - for example when using GC and a large amount of virtual memory. Your 3640 was basically second generation hardware. First were the CADR and then the initial 36 range. Later generations were slightly faster, supported newer hardware (SCSI, NuBUS, VMEbus, ...) and could be embedded into other machines (like the UX boards for SUNs or the MacIvory boards for Macs).