The Internet Mail should have zero impact unless you are checking (auto check, etc.) or sending email during your gaming.
The web shield monitors http port 80 traffic it shouldn't have any impact on pings as that doesn't use the http protocol and as such won't be monitored. I don't doubt you are experiencing problems with the game, but ping shouldn't be impacted by either program. So I'm at a loss as to why it is happening and more so that pings go down when one is disabled.
You mention:
With resident protection disabled I get <300ms ping times when it's enabled it skyrockets to over 1400ms, I've tested this multiple times and it is definitely caused by Avast I can literally see the change as soon as I disable On-Access Protection.
This is a little more than just the web shield and internet mail and includes all the shields including the standard shield, the main scanning engine. If the game is constantly updating files (logs, etc.) on your system then the standard shield could be monitoring/scanning that activity, depending on the sensitivity and the file type ?
Unfortunately I'm not a gamer and don't know if it uses the http protocol for the game interaction or what ports they use ?
Hopefully one of the avast users who are gamers will see this, Perhaps .