Right now, your security combo should be fine enough considering that your laptop is able to handle them pretty fine. Avast can be a hogger at times though. You could try Microsoft Security Essentials alternatively. It isn't a hogger and doesn't give false positives that often and is the most recommended by all security professionals here. If you are facing issues that MBAM doesn't fix, you could use SuperAntiSpyware too (though I don't recommend running them all at the same time as they can interfere with each other). Other than that, your security combo seems pretty fine to me consider they don't cause any problems.