Memory Information
	RAM Speed SIMM type On Board RAM Number of SIMM Slots Supported sizes in MB Maximum RAM Virtual Memory On Board VRAM Number of VRAM slots	80ns 72 pin 4MB* 4 4, 8, 16, 32 132MB** 1GB 512k 2

Notes

*There are two different versions of the 650 logic board. The Centris 650 shipped with 4MB soldered on board, the Quadra 650 with 8MB soldered on board. The maximum RAM is 132MB and 136MB respectively. **The Quadra 650 uses the 8MB logic board for a maximum of 136MB. DO NOT USE COMPOSITE SIMMS IN THE CENTRIS/QUADRA 650! The Centris/Quadra 650 memory circuitry allows any supported SIMM size to be installed into any SIMM socket in any order, and they can run with partially populated banks. It doesn't support 1MB, 2MB or 64MB SIMMs. The Centris/Quadra 650 uses "memory interleaving" which occurs when like SIMM pairs are used (for example: two 8MB SIMMs). This allows the memory subsystem to perform certain operations faster. Basically, it allows the memory subsystem to write to the same memory address in different banks of memory before incrementing the address. Depending on how memory intensive the application, this can improve performance by 5 to 10%.

32-BIT Information

This system has 32-bit-clean ROMs allowing it to take advantage of more than 8MB of physical RAM under System 7 by enabling 32 bit addressing in the Memory Control Panel.

VRAM Information

The Centris 650 has two VRAM SIMM slots capable of supporting two 256k VRAM SIMMs rated at 80ns or faster. A total of 1MB of VRAM is possible.