CraigB
2
The avast default settings are the best for a balance between speed and protection, what i would suggest is removing defender from your system, although defender can be run beside avast it is rather pointless as avast is far better abled to do the job as defender has a low detection rate and all it is really doing on your system is sucking resources.
If you want to run a second opinion scan periodically then Malwarebytes is your best choice.