I don't have any of the old papers / results. But my recollection is that the Lisp workstations greatly outperformed LISP on a contemporary VAX for a given cos

I don't have any of the old papers / results. But my recollection is that the Lisp workstations greatly outperformed LISP on a contemporary VAX for a given cost, in part because of the workstation's microcoded instruction set tailored to Lisp. Over time, though, commodity hardware increased significantly in relative performance simply due to the economies of scale in producing it. You might've been able to buy a Xerox workstation for, say, $15K-$20K, while a VAX box was over $100K. BUT for a production system, the VAX could run multiple Lisp processes at the same time. (I'm guessing at costs here, it's been too long.) Also, Richard Gabriel did a bunch of Common Lisp benchmarks, might help to look for them. (Great fellow.) The real threat to Symbolics et al, circa 1987, was things like Gold Hill Common Lisp running on, say, a IBM PC/AT with a 286 chip and maybe a meg of memory. At, perhaps, $3,000. It ran pretty fast, the Gold Hill tech folks were very good. But GHCL had an unsophisticated development environment compared to Symbolics / Xerox. As excellent as the workstation environments were for development, a market demands that you eventually deliver a cost effective product into customers' hands. (Or is that too much old-think?)