At what point does white hardware perform equally to black hardware, ie: a mono turbo slab?
This article compares x86 and back hardware around the time it was introduced.
http://www.simson.net/ref/NeXT/nextworld/93.5/93.5.Sept.Feature1.htmlit concludes:
"So how does Intel hardware stack up against the Motorola standard? As a group, today's NEXTSTEP-compatible PCs are slightly faster and considerably cheaper than NeXT's late hardware."
Just to add: I think CPU performance was better from the time an intel version of NS was introduced.. lagging was video performance (like the availability of 32-bit color and video-it) however this was soon solved with various video card options and the screenmachineII for NS intel.