Rating the speed ,

of a system running NEXTSTEP isn't as simple as comparing MIPS and WINMARKS in the Windows world. While it is easy to gauge the speed of a computer's CPU and disk, NeXT's Display PostScript system complicates graphics benchmarking. Unlike Windows, NEXTSTEP doesn't draw its windows directly on the screen. Instead, windows are drawn in off-screen buffers and then block-transferred to video memory. That's what gives NEXTSTEP its characteristically smooth window manipulation. Gone is the need for high-performance graphics accelerators. NEXTSTEP only needs a fast CPU and a clear path between the CPU and the video memory.

Four factors therefore determine how fast a computer is: the speed of its CPU; the speed that data can be transferred from the computer's system RAM (DRAM) to video RAM (VRAM), which determines how fast windows can be drawn and updated; the speed at which data can be transferred from one part of VRAM to another, which determines how fast windows can be dragged on the screen; and the disk's data transfer rate. Our benchmarks directly tested these four aspects of system performance. The graphics performance numbers are indexed to the speed of a NeXTstation Turbo Color.

To get an overall measure of system performance, we created a user benchmark that looked up several hundred words in the Webster dictionary. This exercised the system's drawing capability, interprocess communications, and disk-access speed.

Lastly, since developers are primarily interested in the speed at which a computer can compile their programs, our developer benchmark timed the system's speed while compiling the source code for NEXTSTEP's BusyBox demonstration application.

We believe the Webster and Compile benchmarks to be better indicators of real-world performance than raw performance numbers for individual components.