8 MiB, expandable to 132 or 136 MiB (80 ns 72-pin SIMM)
Quadra 650 with tray-loading CD-ROM drive
The Macintosh Quadra 650 and the Macintosh Centris 650 are two closely related personal computers that are a part of Apple Computer's Quadra and Centris series of Macintosh computers, respectively. When the Centris 650 was introduced in February 1993 alongside the smaller Centris 610, it was intended as the start of the new midrange Centris line of computers, a niche formerly occupied by the Quadra 700 which was discontinued. However, that proved confusing, and the Centris 650 was renamed to Quadra 650 in October 1993, with the CPU upgraded from a 25 MHz to 33 MHz. The Quadra 650 was discontinued without a direct replacement in September 1994, although the Power Macintosh 7100, introduced a few months earlier, which used the same case as the 650 (originally used on the Macintosh IIvx), had a similar target audience.
There are two versions of the Centris 650: One with 4 MiB of RAM soldered to the logic board and an FPU-less Motorola 68LC040 CPU, and one with 8 MiB of logic board RAM, a full Motorola 68040, and added an onboard AAUI port for Ethernet. The higher-end model also came with 1MB VRAM installed, enabling 16-bit color at 640x480 resolution. The availability of 16-bit color was significant, as it was the standard bit depth of Apple's then-new QuickTime video standard. The Quadra 650 is also available in the 4 MiB and 8 MiB onboard RAM variations, but always has the 68040 and AAUI.