Memory Upgrade: Centris 650 and Quadra 650

The Centris 650 has 4 MB or 8 MB soldered to the motherboard; the Quadra 650 has 8 MB on the motherboard. Each has four 72-pin SIMM sockets for memory expansion.

Quadra 650With the rear of the computer away from you, you will see 4 SIMM sockets in the front center of the motherboard. Although you can fill each individually, if you match the speed and capacity of paired SIMMs, the 650 will use memory interleaving, which can be 5-10% faster.

Each RAM socket can be filled with a 4 MB, 8 MB, 16 MB, or 32 MB SIMM – they need not be of the same capacity, although you must use matching pairs to take advantage of memory interleaving. (There is no support for 1 MB, 2 MB, or 64 MB SIMMs.) The 72-pin SIMMs must be 80ns or faster. For best stability, all SIMMs should be of the same speed.

Centris 650 and Quadra 650 page from Apple Memory Guide.

Centris 650 and Quadra 650 page from Apple Memory Guide.

Special Resource: Dale Adams on Interleaved Memory on Centris 650 & Quadra 800

VRAM, Where More Memory Means Less Speed

The 650 ships with 512 KB VRAM on the motherboard. You can upgrade this to 1 MB by installing two 256 KB VRAM SIMMs in the VRAM sockets beneath the floppy drive.

Special Resource: Interleaved Memory in the Centris & Quadra by Dale Adams

Keywords: #centris650 #quadra650

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