https://www.av-test.org/en/antivirus/home-windows/windows-10/october-2016/
Avast with flippin FULL 6 POINTS THIS TIME 
Congrats.
I’ve never understood how AV-Test reach their performance rating…
Avast is one of the lightest AVs and doesn’t slow the PC down.
Avast also used to score highly on Performance and usability, but this results shows a nose dive on performance.
Average influence of the product on computer speed in daily usage
Avast used to be very light on systems.
But why their score is that low for performance - a meagre 3.5 for avast out of a max. score of 6.
So they experienced slow loading of webpages, slow download of files and installs,
software running slow on the OS and slow copying files
all due to the influence of the AV solution packet.
Windows Defender scored a full half point higher in that test than Avast did (4.0).
Has anyone here an explanation for this bad performance score.
Personally I experienced that avast free runs better on an acer laptop than for instance on lenovo. 
polonus
We really have no idea why it might differ so much, given that the same tests are run for each program and presumably on the same settings as before.
Doing less is going to produce a lessor hit on performance. What is needed is a comparison of previous results to see if that is their median score.
All I can offer is avasts continual striving to give more protection.
I know that I do a custom install that is extremely minimal, a lot of these new modules, etc. I don’t have installed.
Interestingly I have just bought a new Acer notebook (Aspire F 15), same minimal installation and a similar usage.
But it is lightning quick, given it is on Win10, has an Intel i5-7200U 2.5Ghz (+ turbo boost) 8GB DDR4 RAM, with a 256GB SSD and 1TB HDD.