The Mac Plus uses the same 8 MHz 68000 CPU found in the original Macintosh and the 512K Fat Mac. The attached hard drive is a 160 MB Quantum, and the computer has 4 MB of memory. Because it is an older design, the Plus is generally considered to be about 15% slower than the 8 MHz Mac SE and Classic. Since Speedometer 3 sets the Classic to 1.0 for its tests, the numbers will quickly show where the Plus falls short.
The system was tested on 2000.10.08 using System 7.5.5. Results are relative to a Mac Classic, which rates 1.0. Numbers are rounded off to two decimal places.
The first set of numbers compares performance at different cache settings.
cache CPU graphics disk math 32 KB 0.87 0.91 0.67 0.99 64 KB 0.87 0.91 0.67 0.99 128 KB 0.87 0.91 0.67 0.99 256 KB 0.87 0.91 0.57 0.99
The cache setting should have little influence on non-disk tests, which these numbers bear out. With this particular setup, cache size makes no appreciable difference except at 256 KB, where it actually reduces disk performance.
The Mac Plus isn’t quite as slow as conventional wisdom would have us believe. Hard drives vary from setup to setup, but SCSI throughput has always been the Plus’ Achilles’ heel. Other than that, the Plus offers 87% of the CPU performance of the SE and Classic, 91% of the graphics speed, and almost identical math performance. This means it is 9-13% slower, not the 15% usually claimed.
Speedometer 4 and other benchmark tests don’t run on 68000-based Macs.