However, the cache slot was never meant to host a CPU, and the cards are much bulkier, in every dimension, than the cache cards they replace. The result, at least in the Performa 6400, is a tight fit. Curiously, the Sonnet and Newer cards place the CPU on opposite sides. The Sonnet card is bigger but seems to fit better. However, both companies' cards installed with minimal fuss considering the tight quarters.
Software installation is a breeze.
With each card, you just copy an extension to the System Folder and you're ready to go. We tested the cards by running MacBench 5.0 and MetaCreations' Bryce 4 in Mac OS 8.6. As you might expect, the upgrades provided only a modest boost to the MacBench Disk scores. The other cards, all with 300MHz CPUs, showed little variation in performance. Not surprisingly, the cards showed the greatest variation in MacBench Processor scores, a measure of pure CPU speed.