I use OS 10.3.9 running (with all updates) Catalyst v3.32h25 with Decklink drivers: DeckLink_Macintosh_v4.7.1 - All OS.dmg
can be downloaded from their site - 25M though....
never had a problem - seems to work fine

if using 10.4.6 - use: DeckLink Macintosh 5.6 - 10.4 only.dmg

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