Power Macintosh 8500

Memory Information
RAM Speed
DIMM type
On Board RAM
Number of DIMM Slots
Supported sizes in MB
Maximum RAM
Virtual Memory
On Board VRAM
Number of VRAM slots
Cache DIMM slot
Cache DIMM size
70ns
168 pin
0
8
4,8,16,32,64
512MB
1GB
See VRAM
See VRAM
Yes
1MB
Notes
The Power Macintosh 8500/120 uses DRAM Dual In-line Memory Modules (DIMMs) instead of DRAM SIMMs. Whereas SIMMs have 72 pins, DIMMs have 168 pins. The extra pins provide a 64-bit data path, compared to a 32-bit data path for SIMMs. In addition, DIMMs do not have to be installed in pairs like the SIMMs on earlier Macintosh models. (However, to take advantage of memory interleaving, the DIMMs should be installed in paired slots.

Important: The Single In-line Memory Modules (SIMMs) used in previous Macintosh models are NOT compatible with the Power Macintosh 8500/120.

Important: This computer also uses VRAM DIMMs (112-pin 70ns or faster) instead of VRAM SIMMs. The VRAM SIMMs used in earlier Power Macintosh models are not compatible.

Memory Configurations

The Power Macintosh 8500 logic board has eight DRAM DIMM slots, each with a 64-bit data bus. You can increase the computer's DRAM to a total of 512 MB using 5-volt, 64-bit-wide, 168-pin fast-paged mode, 70ns DIMMs.

Note: The Power Macintosh 8500 does not have any main memory soldered to the logic board. At least one RAM DIMM must be present for the computer to operate.

DRAM DIMMs can be installed individually; however, if you wish to take advantage of the computer's interleaving* capability, which provides maximum performance, you must install the DIMMs in matching pairs and in paired slots (A1 and B1 first, then A2 and B2, and so on).

*Memory interleaving allows the computer to read or write to its memory while other memory reads or writes are occurring, thus providing for faster performance.

For a pair of DIMMs to function as a single 128-bit wide pair, they must be the same type and size.

Note: DIMMs purchased from different manufacturers can be paired as long as they are the same size and speed.

VRAM Information
"On Board" in context of the Power Macintosh 7200, 7500, and 8500 indicates that 1 or more VRAM slots are taken up with DIMMS when they leave the factory: thus, the 7200 has 3 available VRAM slots, while the 7500 and 8500 each have two available to reach the 4 MB VRAM maximum.

The Power Macintosh 7200, 7500, and 8500 all support the same type of VRAM DIMM. The 7200 has VRAM soldered on the logic board. The Power Macintosh 7500, 8500, and 9500 have no VRAM soldered on the logic board. VRAM is expanded on the Power Macintosh 7200, 7500, and 8500 by adding VRAM DIMMs to the expansion slot(s) on the logic board. The VRAM DIMMs must be 112-pin fast-paged mode, with 70ns RAM access time or faster. The Power Macintosh 9500/120 VRAM is expandable by adding VRAM DIMMs to the video card.

NOTE: Power Macintosh 9500/120 customers can get a VRAM upgrade from ATI Technologies, Inc. No VRAM upgrade is available from Apple.

Power Macintosh
Family            VRAM Included             Maximum
7200                 1 MB Logic Board                4 MB
7500                 2 MB via DIMMs                  4 MB
8500                 2 MB via DIMMs                  4 MB
9500/120             2 MB on video card              4 MB


Please send any comments on this page to:
G.Mills@compserv.gla.ac.uk
(George W. Mills, Computing Service, University of Glasgow)