User Guide
Mac Pro Troubleshooting — General Information 141
DIMMs for Mac Pro must t these specications:
667 MHz, FB-DIMMs•
72-bit wide, 240-pin modules•
36 devices maximum per DIMM•
Error-correcting code (ECC)•
Important: For proper operation of Mac Pro computers, Apple recommends using only Apple-
approved Mac Pro FB-DIMMs. Refer to GSX for Apple FB-DIMMs service part numbers.
PCI Express Cards
The Mac Pro logic board includes one double-wide PCI Express graphics slot and three PCI
Express expansion slots, for a total of four slots. The computer comes with a graphics card
installed in slot 1. You can install additional PCI Express graphics and expansion cards in the
remaining three PCI Express expansion slots.
Important: Combined maximum power consumption for all four PCI Express slots must not
exceed 300 W.
Slot 1: Double-wide
PCI Express graphics
(graphics card installed)
Slots 2–4: PCI Express
Note: Port 2 of the ATI Radeon X1900 XT graphics card is compatible with the Apple DVI-to-video
adapter. See KnowledgeBase article 304910.
Internal Cabling Matrix
The table on the next page lists all Mac Pro internal cables that connect to the logic board and
are not part of a larger subassembly. Following the table is a map of the logic board connector
locations, which are listed in column 5 of the table.