yup. me too. i think after using norton and Bit Defender, Avast is still the best. And it's design is quite unique compared to others
I would shift my attention to either the Kaspersky product or Nod32 by ESET. both of these will offer all of the protection you need and more. For ease of use go with Nod32 or for the ultimate protection use Kaspersky. I currenty run both on different systems so i can walk customers through issues. As for a free solution i have recently switched from AVG to Avast. I have installed AVG on around 50 systems over the years and up until three months ago i have never had major issues with it. Thats when i started to see things get past AVG. Maybe is was just a miss by one of their updates i don't have proof but it made me look elsewhere.
sounds like you have 2 products installed on one machine. if that's true then that is likely the PC is bogged down.
I am using kaspersky anti virus software and quite happy with its performance , its working quite well for me
Avira and Bitdefender both are good antivirus and would never slow down your startup speed. I am currently using Avira total security and I have not faced any problem even now. So it's good to use.