For the 'high CPU in v7' FAQ (https://forums.comodo.com/install-setup-configuration-faq-cis/solving-hi-cpu-problems-v7-draft-t102642.0.html;msg746160#msg746160
One solution not to do with old computers, but will cause people to come to this FAQ, is that version 7 causes a virus scan to happen, even if you don't have any scheduled. I only found the workaround after some Googling and one person's post.
People for the past 6 months or so using Version 7 are seeing it hogging and doing a lot of work, with high memory usage, slowing computers down to a crawl as they crackle non-stop doing SOMETHING. It turns out that this is because of a hidden virus scan. Go to 'Tasks' in the top-right hand corner, 'Advanced Tasks' at the bottom, and click 'Open Task Manager' (second option down on the right hand column). You'l lsee it right there, as well as how long it's been going and how many percent it's done so far. Just click the stop button and it's gone. Good as new... until next time.
No need to change to a different firewall/antivirus, no need to uninstall and revert to an older version, no need to end process in Windows Task Manager, no need to worry about the NSA (one person did). Just a few clicks away.
Becomes more of a problem if the scan starts up in the middle of a multiplayer game though, I'm sure.