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SDRAM Devices

The memory controller in the Grackle IC supports 1 Mbit, 4 Mbit, 8 Mbit, 16 Mbit, 64 Mbit, and 128 Mbit SDRAM devices that are PC-100 compliant. The speed of the SDRAM devices should be rated at 125 MHz (8 ns) or faster. The Grackle memory controller IC is configured to detect devices with a CAS latency as low as 1 and as high as 3. The Grackle IC is configured to support the slowest SDRAM bank it detects in the system. The access time from clock at CAS latency of 3 should be 7 ns or faster. Burst length should be at least 4 and the minimum clock delay for back-to-back random column accesses should be a latency of 1 clock.

IMPORTANT

The DIMM modules used in any previous Power Macintosh or Power Macintosh G3 computer model are not compatible with the Power Macintosh G3 described in this note. The SDRAM DIMM modules must be PC-100 compliant, 168-pin, 3.3-volt, unbuffered, and rated at 125 MHz (8 ns) or faster.