Apple Macintosh System 7.5 - Manual (Page 44)

AppleTalk network type
Installing System 7.5 over an EtherTalk network takes 5 to 10 minutes,
depending on network traffic.
Installing over a LocalTalk network takes several times as long as using
EtherTalk, again depending on traffic.
AppleShare server type
If you have more than one AppleShare server, choose the fastest model
available as the upgrade server. The performance obtained from the Installer
on the network depends on the network’s transmission speed and on the
processing speed of the Macintosh computer running the AppleShare server
software.
Use staggered installation: The System 7.5 Installer allows simultaneous
installations, but this degrades performance. Avoid having large numbers of
users install the software from the upgrade server at the same time.
How the upgrade server is used
If the upgrade server is also used as a general-purpose AppleShare server,
users accessing documents or programs may experience poor performance
while others are installing system software.
Notify the server’s users of this temporary condition.
41 Setting Up the Group Upgrade Server