8 or 16 MB, expandable to 1 GB (70 ns 168 pin DIMM)
The Power Macintosh 7500 is one of the first PCI capable Macs manufactured by Apple Computer. It was released alongside the Power Macintosh 7200, and the Power Macintosh 8500 in October 1995. The 7500 had a PowerPC 601 processor rated at 100 MHz that was replaceable via a daughtercard. It also featured full composite video and s-video input capability, but no output, as the 7500 was designed to be a video conferencing system, not a multimedia editing machine—this was the 8500's task. The 7500 and 7200 featured a unique swing open chassis termed "Outrigger" by Mac enthusiasts. The entire motherboard was accessible to the user after the hinged drive sleds were opened, allowing for easy upgrades.
In the 7500 and related models, the main bus runs at 45MHz or 50MHz (set by the CPU daughtercard), and the CPU at integer or half-integer multiples of this speed. The bus can be temperamental with sensitivity to different kinds of RAM or of L2 cache, which could cause problems with aftermarket CPU cards trying to increase the clock speed.