Hi @Davie260563,
I’d note that while my above comment is true in general, I wouldn’t expect 52-70 degrees to noticeably affect the camera stream, especially towards the lower end. A Raspberry Pi 3B will automatically throttle itself when it gets above 80 degrees, (in which case there’ll be a message that “Throttling has occurred” on the System page), but you don’t seem to have reached that point so I’d expect something else is causing the lag issues.
Beyond the (mostly hardware considerations) I mentioned several months ago, there have also been a number of software improvements. If you’re not already on the latest Companion software (0.0.30) I’d recommend you update (via the System page).
It may also be worth downloading QGC 4.1.4, which has some video decoding fixes that can reduce flickering/lag (you may need to swap between different decoding options - click the purple QGC logo in the top left, and select Application Settings)
I understand you’re in the process of switching to using Eiva’s NaviSuite, but it would be useful to understand whether the video issues are from the topside struggling to decode or whether it’s a Companion software/ROV hardware issue. If the video works fine in QGC 4.1.4 then presumably Eiva will need to fix something on their end, but if it’s just as problematic on 4.1.4 then it’s most likely a Companion or hardware problem that we can hopefully help you to sort out 