BI cpu usage

Seeing the same behavior on my install, with memory climbing within a minute or two to 100% then the machine starts to swap and grind to a slug in performance. Have been running the same hardware config for a year or two with no issues, had to reinstall/rebuild earlier this week with clean install of Windows 10 Pro on same hardware. Running 12 cameras, always ran about 4-5GB before, now consuming all 8GB on machine.

My install ran fine since 5/26 after rebuild until last 24 hours where this started. I see two windows updates added KB 3173427 and KB4019474 added in past 2 days. Rolling those back to test now. Same issue repeated when I rolled back BI to 4.5.1.x and 4.5.5.x
Update your video card drivers. As said before. Search memory leak. This has been fixed for long time now.

Also, I bet you changed something. i.e. to use Intel HD acceleration. This is what causes it. If you turn off Intel HD acceleration that will also fix it. Although that will increase CPU usage. Simply update your video card drivers and this will solve you memory leak issues.
Nothing to do with blue iris.