Wow, we need to make this a sticky post
BI5 v54711 x64 | Win10 21H1 | Dahua IPC-HDW5231R-ZE, Foscam R2, Ertech 4MP, Neos2, 2 SD cams | BI5:1 i5-3330, 16GB Ram, Multiple SSD and HD, Homeseer 2 HSPhone, TVMosaic | BI5:2 Ryzen 1800X, 16GB Ram, Multiple SSD and HD, Homeseer 4, Emby, DVBViewer.
Surprisingly, not much... 2-3 percentage points. Was sitting at 4-5% CPU usage overall, now I'm at 7% idle, increasing to 10% when I "stimulate" the cameras. (still sitting on the bench, so I wave my hands across their fields of view)