For the past few months I've noticed that my internet browsing is noticeable slower - sometimes in Firefox it takes 15 minutes to download a 10 MB file! - and at times my program-loading speed is much slower as well. This more or less correlates with when I accidentally allowed my free Comodo Firewall to update itself to a more robust version which contains antivirus scanning, sandbox, etc. as well as some PUP bundles. However, I already have Avast antivirus running with file system / web shields, "DeepScreen", "Home Network Security", etc., though the free version doesn't have sandbox capabilities.
Now that the newer Comodo is acting more antivirus-y, could it and Avast be clashing with each other and possibly be contributing to slower browsing? If so, do I have to uninstall one of them and switch to a different combination of firewall + AV, or is there something I can do with settings?