http://web.archive.org/web/20030516064654/www.truevision.com/support/TARGA/2000/NuBus/UserManuals/TARGAMacInstallGuide.pdf

Mentions OS 7.5.5 or later, Quicktime 2.5 or later, Most powermacs.

http://web.archive.org/web/20040701010747/www.truevision.com/support/HTMLPage.asp?HTMLPages_ID=28

Recommended Macintosh System

Apple Quadra 650, 660(AV), 700, 800, 840AV, 900, 950

24 MB RAM or greater (32 MB recommended)

ATTO Silicon Express IV

One or more AV-rated fast/wide hard drives

Apple System 7.5.1 (Later versions may work but have not been tested).

QuickTime 2.1

Apple Power Macintosh 7100/80 and 8100

24 MB RAM or greater (32 MB recommended)

ATTO Silicon Express IV

One or more AV-rated fast/wide hard drives

Apple System 7.6.1

QuickTime 2.5