I have Avast uninstalled and I can pull well over 900 Mbps down and when I install it and reboot. The speeds drop to well under 300 Mbps and the connection is all over the place. Randomly blocking local sites to routers, switches, even other computers when it is still set to Private.
I uninstall Avast and everything works perfect. Issue with an update?
I even unblock apps from the firewall to allow access too and it does not work. I have to disable Avast then things works fine, except speed.
900 Mbps down?
Give me your connection 
Randomly blocking local sites to routers, switches, even other computers when it is still set to Private.As has been told in many other threads already, there is a known issue with the avast firewall. Disable port scanning it and the problem should be solved.
Connection is great! haha
Randomly blocking local sites to routers, switches, even other computers when it is still set to Private.As has been told in many other threads already, there is a known issue with the avast firewall. Disable port scanning it and the problem should be solved. [/quote] I have already disabled this but the speeds were still being cut by 2/3. I was barely able to get 300 Mbps and connection was not consistent. Without avast installed connection is very consistent.
How do you check the speed ?
my ISP has a serer locally that it is used to test. as for as the jitter this is done simply by doing ping tests.
Best way is to download a huge file, something that give you a 10 minute download time
Then turn on avast and repeat it while taking the time, how big is the difference?
Disabling is still not enough to get the speeds back. I have to physically uninstall it to get speeds back.
What if you just uninstall Avast firewall ?
If disabling the firewall is not helping, disable the shields one at a time to see which one is causing the problem
I have tried to disable each of the shields one at a time and finally everything is disabled and still does not fix the speed issue. I had just updated my license to premier also.
I have a solid state drive and two 1 terabyte HDD running in RAID 0 so performance is definitely there. Running a speed test without Avast and I get speeds closer to 960 Mbps. There is no way I would install the version that I had boughten for decent money if it drops my connection clear down to less than 300 Mbps. I did try Total Defense and all shields it only dropped my speed by about 40 Mbps, which is still doable.
If I disable all of those services to make my speeds back to where they were, why would I even have paid for Avast Premier?
I suggest to contact avast and have them take a look at things.
Feel free to contact support: https://support.avast.com/support/tickets/new
This did not get very far as they wanted me to pay for support. I just simply uninstalled it and looking for another AntiVirus that will not lose have of my gig service.
Also found out that if you get a discount on service, they will charge you the full amount a month later. This has happened twice to me so far in the 5+ years I have used Avast.
Goodbye Avast. Tired of all of the issues!
There is no payment requited to use the ticket support. ???
They told me that I needed the premium support
Who told you ??? Never heard of that before and needs to be investigated.
Do you have the details ???
Did you even created a ticket ?
A avast av subscription isn’t going per month but per year.