@RPGaff From their last post, it sounded like it was possible only the later cutscenes lagged, although maybe the issue is always present and simply a bit more subtle earlier in the game. I'd still like to test though: it's worth knowing that this problem shows up on a Bootcamped Mac if and only if it's using an eGPU. The graphics drivers for macOS are completely different than what everyone else has, so while the game might behave exactly the same way, I'm not going to assume.
Thanks for flagging the other thread though. I haven't been able to keep up with this forum (really at all), so I'd only seen one other report and wasn't sure whether it was a coincidence.
I can confirm that this definitely isn't just a Mac/Bootcamp issue, but there does seem to be an eGPU common connection. I'm running Windows 10 on a PC (Intel Tiger Lake i7/16 GB RAM) with external eGPU and a Vega 64 and I get exactly the same slow motion cutscenes/stuttering during pre-rendered scenes (and loading screens).
What is more annoying is that not only does the cutscene run at a terrible framerate, but often there is an in-game engine scene which follows it (particularly common towards the end of ME1) which seems to start before the cutscene is finished, so you hear the overlapping audio of both scenes and miss the beginning of the in-engine scene.
