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TECHINFO-0020989
TOPIC
Is my PowerBook computer based on NuBus or PCI architecture? What is the difference between NuBus and PCI? Is there some advantage to PCI?
I need to know so I can use the correct 1710AV recovery disk on for this computer and for installing some other applications.
DISCUSSION
All Macintosh PowerBook computers prior to the PowerBook 3400 were NuBus-Based computers. The Macintosh PowerBook 3400 series computers were the first Peripheral Component Interconnect (PCI)-based Macintosh PowerBook computers. Specifically, the media expansion bay of the PowerBook 3400 series computers is based on PCI architecture.
What is NuBus?
NuBus refers to the expansion bus used in many Macintosh computers. Apple implemented the NuBus protocol in a number of its products before incorporating PCI. NuBus is a trademark of Texas Instruments, Inc.
What is PCI?
PCI (Peripheral Component Interconnect) is a high-performance expansion bus architecture that was originally developed by Intel to replace the traditional Industry Standard Architecture (ISA) and Enhanced Industry Standard Architecture (EISA) buses found in many 80x86-based PCs.
PCI and NuBus: A comparison
PCI offers significantly higher performance than NuBus. More specifically, a PCI card can provide performance up to three times faster than that of a similar card on even the fastest computers with NuBus slots.The following chart/table provides a feature-by-feature comparison between the PCI and NuBus specifications:
| PCI | NuBus | |
|---|---|---|
| Bus Speed | 33 MHz | 10 MHz |
| Theoretical Maximum Throughput | 132 MB per second | 40 MB per second |
| Maximum Number of Slots | 4 per bridge; 256 bridges | 6 per bridge; 14 bridges |
| Real Throughput | 90 MB per second writes; 45 MB per second reads | 32 MB per second writes; 20 MB per second reads |
| Software | Name Registry, Open Firmware | Slot Manager |
For more information about PCI bus architecture please refer to the TIL article TECHINFO-0017732 titled, ":PCI Expansion Bus Architecture Description.": 
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