https://www.forticlient.com/downloads You can download it below "Get Forticlient 6.0 for Windows" . Its known to have very high detection rates when it comes to signatures. Also there is anti-exploit feature and website blocking... Not sure if there is any sort of behaviour based module, some of the things like "Dynamic threat detection" is turned off which can be turned on. Would be worth some test runs and tests yes ? There is also a option to turn on "sandbox analysis" but i guess it needs to be installed and configured somehow.
It does have one of the best webfilters. It's also very light, that's why i run it on my 1.2 ghz dual core with very slow 5400 RPM hdd. Running Defender or other AV on that machine renders it unusable. Detection rate is quite good, there's no HIPS and PUP detection is quite poor. You can also export its .conf file to a file, then edit it and import back. By editing a .conf file, you can "harden" it even further, but you have to know what are you doing. But in my opinion, its the best AV for low-spec PC computers hardware. And for Sandbox analysis, you need FortiGate appliance for that. -sepik