CPU spikes very high when a group of cams trigger

[Mike A.]

I have a group of 3 cams which are triggered from a motion sensor or from one another. i.e., If the motion sensor trips or one cam is triggered, then they all trigger. Been working as I want fine for a long time.

Noticed today that CPU is spiking way up to 70-100% when the cams trigger together. Never noticed that it would go up much in the past. Makes sense that it could go up some but not sure why so high now and in this case given:

• all cams already are recording continuously so there's no change as far as what's recorded when triggered.
• no motion sensing is active in BI, all are using on-cam IVS or are triggered from the motion sensor so no added motion analysis involved by BI (beyond whatever timing to end the trigger).
• no cams display full screen when triggered so the console view doesn't change.
• no CodeProject or DeepStack AI in use for those cams so nothing going on in the background there.

I see the same for another group which operates the same way other than not involving a motion sensor.

CPU normally sits at ~20-25% with console up. Yes, using substreams on all cams. Haven't updated BI for a while (5.7.4.1). Could have changed after some update but didn't notice I suppose. No recent Windows updates.

Why does it go up so much when there's not much changing as far as the streams for viewing, recording, motion, or AI?