{"id":579,"date":"2023-07-11T23:51:27","date_gmt":"2023-07-11T23:51:27","guid":{"rendered":"https:\/\/mac84.net\/web\/?page_id=579"},"modified":"2023-07-11T23:53:22","modified_gmt":"2023-07-11T23:53:22","slug":"vintage-macintosh-scsi-data-transfer-rates","status":"publish","type":"page","link":"https:\/\/mac84.net\/web\/vintage-macintosh-scsi-data-transfer-rates\/","title":{"rendered":"Vintage Macintosh SCSI Data Transfer Rates"},"content":{"rendered":"\n

This is a clone of a now dead Apple page (archived version, KB TA29470<\/a>) where SCSI data transfer rates were listed. This is an attempt to replicate that page. If you prefer a spreadsheet version, see this link<\/a>.

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: <\/strong>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\/.<\/em><\/p>\n\n\n\n

<\/p>\n\n\n\n

Macintosh Model<\/strong><\/td>SCSI Chip<\/strong><\/td>Max Data Transfer Rate<\/strong>*<\/strong><\/td>SCSI Notes<\/strong><\/td>Additional Notes<\/strong><\/td><\/tr>
Macintosh 128K<\/td>N\/A<\/td>N\/A<\/td><\/td>This system does not have SCSI capabilities.<\/td><\/tr>
Macintosh 512K<\/td>N\/A<\/td>N\/A<\/td><\/td>This system does not have SCSI capabilities.<\/td><\/tr>
Macintosh 512Ke<\/td>N\/A<\/td>N\/A<\/td><\/td>This system does not have SCSI capabilities.<\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh Plus<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh SE<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh SE\/30<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh Classic<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh Classic II<\/td>NCR AM85C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh Color Classic<\/td>NCR AM85C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh LC<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh LC III<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh LC III<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh LC 475<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh LC 520<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh TV<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh II<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIx<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIcx<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIci<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIfx<\/td>Apple SCSI DMA<\/td>3 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIsi<\/td>NCR AM85C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIvi<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh IIvx<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh Centris 610<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Centris 650<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Maicntosh Quadra 605<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Quadra 610<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh 630 family<\/td>Custom IC<\/td><\/td>Note 5<\/td>Includes LC, Performa, and Quadra branded models<\/td><\/tr>
Maicntosh Quadra 650<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Quadra 660AV<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Quadra 700<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1<\/td><\/td><\/tr>
Macintosh Quadra 800<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Quadra 840AV<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1 & 2<\/td><\/td><\/tr>
Macintosh Quadra 900<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1, 2, & 3<\/td><\/td><\/tr>
Macintosh Quadra 950<\/td>NCR 53C96<\/td>5 MB\/sec<\/td>Note 1, 2, & 3<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 5200<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 5300<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 5400<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 5500<\/td><\/td><\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 6100<\/td>Custom IC<\/td>5 MB\/sec<\/td>Note 2<\/td><\/td><\/tr>
Power Macintosh 6200<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 6300<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 6400<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 6500<\/td><\/td><\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 7100<\/td>Custom IC<\/td>5 MB\/sec<\/td>Note 2<\/td><\/td><\/tr>
Power Macintosh 7200<\/td>Custom IC<\/td>5 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 7500<\/td><\/td><\/td><\/td><\/td><\/tr>
— Internal\/external<\/td>Custom IC<\/td>5 MB\/sec<\/td>Note 2 & 6<\/td><\/td><\/tr>
— Fast SCSI (internal)<\/td>MESH Custom IC<\/td>10 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 7600<\/td><\/td><\/td>Note 2 & 6<\/td><\/td><\/tr>
— Internal\/external<\/td>Custom IC<\/td>5 MB\/sec<\/td><\/td><\/td><\/tr>
— Fast SCSI (internal)<\/td>MESH Custom IC<\/td>10 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 8100<\/td>Custom IC<\/td>5 MB\/sec<\/td>Note 2<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 8500<\/td><\/td><\/td>Note 2 & 6<\/td><\/td><\/tr>
— Internal\/external<\/td>Custom IC<\/td>5 MB\/sec<\/td><\/td><\/td><\/tr>
— Fast SCSI (internal)<\/td>MESH Custom IC<\/td>10 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh 9500<\/td><\/td><\/td>Note 2 & 6<\/td><\/td><\/tr>
— Internal\/external<\/td>Custom IC<\/td>5 MB\/sec<\/td><\/td><\/td><\/tr>
— Fast SCSI (internal)<\/td>Custom IC<\/td>10 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Power Macintosh G3<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh Portable<\/td>NCR 53C80<\/td>1.25 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 100<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 140<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 145<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 145B<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 150<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td>Note 4<\/td><\/td><\/tr>
Macintosh PowerBook 160<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 165c<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 170<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 180<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 180c<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook 190<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh PowerBook Duo 210<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook Duo 230<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook Duo 250<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook Duo 270c<\/td>NCR AM85C80<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
Macintosh PowerBook Duo 280c<\/td>Custom IC<\/td>1.5 MB\/sec<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
Macintosh PowerBook 520<\/td>Custom IC<\/td>1.5 MB\/sec<\/td><\/td>Also includes the PowerBook 520c<\/td><\/tr>
Macintosh PowerBook 540<\/td>Custom IC<\/td>1.5 MB\/sec<\/td><\/td>Also includes the PowerBook 540c<\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
PowerBook 1400<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
PowerBook 2400<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
PowerBook 3400<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
PowerBook 5300<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/td><\/td><\/tr>
PowerBook G3<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr>
PowerBook G3 Series<\/td>Custom IC<\/td><\/td><\/td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
SCSI Note ID<\/td>Note Contents<\/td><\/tr>
<\/td><\/td><\/tr>
*<\/td>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.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 1<\/td>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.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 2<\/td>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.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 3<\/td>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.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 4<\/td>The PowerBook 150 only supports external SCSI devices, the internal hard drive is an IDE type drive.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 5<\/td>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.<\/td><\/tr>
<\/td><\/td><\/tr>
Note 6<\/td>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.<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"

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…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/pages\/579"}],"collection":[{"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/comments?post=579"}],"version-history":[{"count":3,"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/pages\/579\/revisions"}],"predecessor-version":[{"id":583,"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/pages\/579\/revisions\/583"}],"wp:attachment":[{"href":"https:\/\/mac84.net\/web\/wp-json\/wp\/v2\/media?parent=579"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}