Every suite or antivirus product will consume resources and slow down your PC. You'll probably notice it when you download a new executable file and the antivirus locks it and scans it, when you launch a program, etc. The security program attaches a module dll to every running process and that ads up to resource usage as well. But we use security to avoid catching a virus because malware will slow us down to a crawl, removing it will require more time. So it is a trade off. In the last mounts I used Kaspersky IS beta and RC, Bitdefender IS, Microsoft Security Essentials beta, Comodo Internet Security and avast Free Antivirus.
- Bitdefender is a bit bloated in my opinion, the lag is noticeable and it remains there after using the suite for a couple of days, maybe they will improve resource usage in a future version.
- KIS 2013 beta was slow as well but the RC was considerably lighter and after a couple of days it was even better. However in this version Kaspersky removed Safe Run for Applications and the Proactive Defense module. I still wouldn't call KIS 2013 a light suite.
- CIS felt lighter than the previous two suites. Of course being a HIPS product you spend some time answering a few pop-ups and that might slow down your workflow, it depends on how you use your PC, if you install new software every day or if you are a gamer and need every bit of power from your PC you probably wouldn't use any Internet Suite.
- MSE and avast! Free Antivirus are of course lighter than any of the above suites and I can't tell for sure if the system felt lighter with avast! but considering that avast! has more protection I would say that it is the lightest antivirus I've used in the past few mounts. Also MSE has considerable more ram usage and that might be noticeable on a PC with less RAM. I also do not use avast Mail and P2P protection or their reputation plugin.
