Power Mac 5400-series

Motherboard Diagram by MacGurus
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The Power Mac 5400, alone among the all-in-one integrated Mac designs, boasts a 32-bit PCI bus architecture and a 64-bit memory bus. With two (2) DRAM DIMM slots, this computer requires JEDEC-standard 5-volt, 64-bit, 168-pin, EDO 60ns DIMMs, which must refresh at a rate of 2k or better. As is true with other Alchemy-based Power Macintosh like the 6400 & 6360-series, FPM memory can also be used, but EDO is preferred due to its superior compatibility.

The more common 4k refresh DIMMs occasionally used in other PCI Power Macs are not compatible with the 5400 motherboard, insofar as they will register only half of their engineered memory density. It should be noted, however, that DIMMs supporting 1k or 256k refresh are compatible with the 5400's PSX memory controller, as are 4k devices based on a 2M x 8 architecture with 12 x 9 addressing. Additional information is available in Power Macintosh 5400 & Performa 6400: Adding Memory (TECHINFO-0019598).

With 8MBs of DRAM soldered to the logic board, the 5400-series typically ships with vacant DIMM slots, for a default configuration of 8MBs. Additional memory may be installed in any slot, in any order, as the PSX memory controller supports linear memory organization only, and cannot interleave. No performance benefit whatsoever derives from installing DIMMs in pairs in this machine.

The maximum amount of usable memory in the 5400-series is 136MB, in the form of two (2) 64MB DIMMs, and including the 8MBs of DRAM soldered on the logic board. Please see Power Macintosh 5400/120: Technical Specifications (7/96)(TECHINFO-0019560) in Apple's Technical Information Library (TIL) for more information.

At the time these Macs were released, the only L2 cache available for them was Apple's 160-pin L2 DIMM, part number M4505LL/A, High-Performance Module for Power Macintosh 5400 and Performa 6400. Fortunately, third-party offerings have filled the gap, so it is now possible to install IDT L2 DIMMs in 512k and 1MB capacities.

Logic Board RAM 8MB.
Supported DIMMs 32MB, 64MB.
Number DIMM Slots Two (2).
Supported VRAM 1MB non-upgradeable DRAM.
Number VRAM Slots None.
L2 Cache Supported 256k, 512k, 1MB
DIMM Type 168-pin, 5v, EDO /64-bit, 2k refresh, 60ns or faster.

As noted, the 5400-series have no VRAM slots on the logic board, and minimal on-board video circuitry, although this Mac's multimedia pedigree is intriguing. Fortunately, this architecture supports 7-inch PCI video cards, including accelerated third-party video cards. VRAM configurations and machine capabilities are hence only limited by third-party offerings.

MacGurus appreciates the gentle corrections of Mr. Pete Sealy to the data on this page.

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