http://www.av-comparatives.org/wp-content/uploads/2015/07/avc_per_201505_en.pdf
Guess whos first 
How many times do we have to say that those test results are totally useless without knowing details of the test?
Its all said in the PDF File…
Avast for some considerable time has been considered light on resources
These results don’t really make any difference, it is entirely dependant on your system setup and how you use it. Your average user is likely to have a unique system setup, Operating System, CPU, RAM, Installed programs, etc. etc.
Real world tests are very hard to emulate and most.
I’m always happy to pass good news on to those
that attend my Avast sponsored Presentations
http://www.screencast-o-matic.com/screenshots/u/Lh/1435858779791-8999.png