This is a clone of a now dead Apple page (archived version, KB TA29470) where SCSI data transfer rates were listed. This is an attempt to replicate that page. If you prefer a spreadsheet version, see this link.
What is the maximum sustained asynchronous data transfer rate for the various Macintosh models?
What SCSI chip is used inside the various Macintosh models?
Note: After May 25, 1999, this article will not be updated. Product specific information on SCSI controller chips can be obtained from the Developer Note for a particular product. You can view and download Developer Notes from the following Web site: http://developer.apple.com/hardware/.
Macintosh Model
SCSI Chip
Max Data Transfer Rate*
SCSI Notes
Additional Notes
Macintosh 128K
N/A
N/A
This system does not have SCSI capabilities.
Macintosh 512K
N/A
N/A
This system does not have SCSI capabilities.
Macintosh 512Ke
N/A
N/A
This system does not have SCSI capabilities.
Macintosh Plus
NCR 53C80
1.25 MB/sec
Macintosh SE
NCR 53C80
1.25 MB/sec
Macintosh SE/30
NCR 53C80
1.25 MB/sec
Macintosh Classic
NCR 53C80
1.25 MB/sec
Macintosh Classic II
NCR AM85C80
1.25 MB/sec
Macintosh Color Classic
NCR AM85C80
1.25 MB/sec
Macintosh LC
NCR AM85C80
1.5 MB/sec
Macintosh LC III
NCR AM85C80
1.5 MB/sec
Macintosh LC III
NCR AM85C80
1.5 MB/sec
Macintosh LC 475
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh LC 520
NCR AM85C80
1.5 MB/sec
Macintosh TV
NCR AM85C80
1.5 MB/sec
Macintosh II
NCR 53C80
1.25 MB/sec
Macintosh IIx
NCR 53C80
1.25 MB/sec
Macintosh IIcx
NCR 53C80
1.25 MB/sec
Macintosh IIci
NCR 53C80
1.25 MB/sec
Macintosh IIfx
Apple SCSI DMA
3 MB/sec
Macintosh IIsi
NCR AM85C80
1.25 MB/sec
Macintosh IIvi
NCR AM85C80
1.5 MB/sec
Macintosh IIvx
NCR AM85C80
1.5 MB/sec
Macintosh Centris 610
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Centris 650
NCR 53C96
5 MB/sec
Note 1 & 2
Maicntosh Quadra 605
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Quadra 610
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh 630 family
Custom IC
Note 5
Includes LC, Performa, and Quadra branded models
Maicntosh Quadra 650
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Quadra 660AV
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Quadra 700
NCR 53C96
5 MB/sec
Note 1
Macintosh Quadra 800
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Quadra 840AV
NCR 53C96
5 MB/sec
Note 1 & 2
Macintosh Quadra 900
NCR 53C96
5 MB/sec
Note 1, 2, & 3
Macintosh Quadra 950
NCR 53C96
5 MB/sec
Note 1, 2, & 3
Power Macintosh 5200
Power Macintosh 5300
Power Macintosh 5400
Power Macintosh 5500
Power Macintosh 6100
Custom IC
5 MB/sec
Note 2
Power Macintosh 6200
Power Macintosh 6300
Power Macintosh 6400
Power Macintosh 6500
Power Macintosh 7100
Custom IC
5 MB/sec
Note 2
Power Macintosh 7200
Custom IC
5 MB/sec
Power Macintosh 7500
— Internal/external
Custom IC
5 MB/sec
Note 2 & 6
— Fast SCSI (internal)
MESH Custom IC
10 MB/sec
Power Macintosh 7600
Note 2 & 6
— Internal/external
Custom IC
5 MB/sec
— Fast SCSI (internal)
MESH Custom IC
10 MB/sec
Power Macintosh 8100
Custom IC
5 MB/sec
Note 2
Power Macintosh 8500
Note 2 & 6
— Internal/external
Custom IC
5 MB/sec
— Fast SCSI (internal)
MESH Custom IC
10 MB/sec
Power Macintosh 9500
Note 2 & 6
— Internal/external
Custom IC
5 MB/sec
— Fast SCSI (internal)
Custom IC
10 MB/sec
Power Macintosh G3
Custom IC
Macintosh Portable
NCR 53C80
1.25 MB/sec
Macintosh PowerBook 100
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 140
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 145
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 145B
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 150
NCR AM85C80
1.5 MB/sec
Note 4
Macintosh PowerBook 160
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 165c
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 170
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 180
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 180c
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook 190
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook Duo 210
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook Duo 230
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook Duo 250
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook Duo 270c
NCR AM85C80
1.5 MB/sec
Macintosh PowerBook Duo 280c
Custom IC
1.5 MB/sec
Macintosh PowerBook 520
Custom IC
1.5 MB/sec
Also includes the PowerBook 520c
Macintosh PowerBook 540
Custom IC
1.5 MB/sec
Also includes the PowerBook 540c
PowerBook 1400
Custom IC
PowerBook 2400
Custom IC
PowerBook 3400
Custom IC
PowerBook 5300
Custom IC
PowerBook G3
Custom IC
PowerBook G3 Series
Custom IC
SCSI Note ID
Note Contents
*
This is a theoretical maximum synchronous sustained data transfer rate. The practical data transfer rate varies depending on many factors, such as SCSI chip transfer rate limit, SCSI driver used, hard drive performance, software applications, cables, and other configurations.
Note 1
The transfer rate of the 53C96 can reach 6MB/sec when using a fast hard drive, provided the cabling is capable of supporting that speed. The cabling and termination of the internal SCSI bus are optimized so that the 53C96 that controls the internal bus can support data transfers at a faster rate (up to 5MB per second with existing faster third-party hard drives). Externally with standard Apple cables, SCSI throughput was rated at 4 MB per second. The improved SCSI performance results in increased system responsiveness when accessing large amounts of data on a fast hard drive.
Note 2
The internal SCSI channel also supports active termination which improves SCSI bus signal quality and reliability through improved transmission line and terminator design. This means that only one terminator is needed at the end of the external SCSI chain. The external channel’s termination also offers a more uniform impedance and cleaner termination scheme. However, because external cabling and termination are less predictable, performance on the external bus could be lower than the internal. Electrically isolating the two channels ensures that changes in external cabling and termination don’t impact the performance of the internal devices.
Note 3
Even though the internal and external SCSI chains are physically different, they are still logically the same, and can therefore, like all Macintosh systems, accommodate up to seven SCSI devices. The added value of the Macintosh Quadra 950 dual-controller design is that the internal hard drive(s) performance won’t be affected by problematic devices (like a scanner) attached to the external SCSI connector. Improvements in signal quality on the SCSI bus result in higher SCSI reliability.
Note 4
The PowerBook 150 only supports external SCSI devices, the internal hard drive is an IDE type drive.
Note 5
The Macintosh 630 family utilizes an internal IDE hard drive, SCSI is only valid for external drives. The transfer rate external approaches 5 MB/sec.
Note 6
These computers have dual-channel asynchronous SCSI. There are two completely separate SCSI buses. The Fast SCSI bus is for internal SCSI connections only. The other SCSI bus is for both internal and external SCSI connections.