Power Macintosh 9500 Series: RAM (DIMM) Specifications (8/95)

Article Created: June 27 1995 Article Review/Updated: 29 August 1995

TOPIC

What type of RAM is required by the Power Macintosh 9500 series? How do I install it?

DISCUSSION

The following information is taken directly from the Power Macintosh 9500 Technical Information booklet provided with each Power Macintosh 9500 series computer.

DRAM

Memory for the 9500 series is added in packages called Dual Inline Memory Modules (DIMMs).

Installation

Apple Computer, Inc. recommends that only an Apple-certified technician install additional DRAM.

DRAM Configurations

Your computer can use any DRAM configuration with DIMMs of these sizes: 8, 16, 32, or 64 MB. The exact configuration depends on the density of the DRAM chips that are mounted on the DIMMs. (The DIMMs support both 2K and 4K refresh rates.)

You can increase you computer's DRAM to up to 768 MB using 16-megabit (Mbit) DRAM technology. The main logic board has 12 slots (each with a 64-bit data bus) where DIMMs can be installed. If the DIMMs are installed in paired slots, the memory subsystem is 128 bits wide, providing increased performance. This is called memory interleaving. To increase DRAM to the maximum of 768 MB, have an Apple authorized dealer or Service Provider fill all 12 slots with 64 MB DIMMs. You can also fill slots with 8, 16 or 32 MB DIMMs.

Note: The 9500 series is designed to expand to a DRAM capacity of up 1.5 gigabyte (GB) using 128 MB DIMMs. However, these DIMMs are not currently readily available and have not been tested by Apple Computer, Inc. for use in the Power Macintosh 9500 series computers.

**IMPORTANT** The DIMMs should be 5-volt, 64-bit-wide, 168-pin fast-paged mode, with 70- nanosecond (ns) RAM access time or faster. DIMMs taller then 1.25 inches cannot fit in to the 9500 computer. The Single Inline Memory Modules (SIMMs) from older Macintosh computers are not compatible with the 9500 and cannot be used.

Adding DRAM

If you decide to have additional DRAM installed in your computer, the DIMMs can be installed one-at-a-time in any order in any of the memory slots. However, if you wish to take advantage of the Power Macintosh 9500 series computers' memory interleaving capability, which provides maximum performance, you must have the DIMMs installed in pairs, and in paired slots. (A1 and B1 are the first pair of slots, A2 and B2 are the second, and so on.) Memory interleaving allows the computer to read or write its memory while other memory reads or writes are occurring, thus providing faster performance.

Paired DIMMs should be the same size and speed. DIMMs purchased for different manufacturers can be paired as long as they are the same size and speed. Article Change History: 29 Aug 1995 - Made minor corrections.

Keywords: kppc,kpci,supt

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