Some of the free antivirus and free trial antivirus software programs perform better than the commercial products because they usually don’t slow down your computer. Many of the more expensive commercial antivirus programs hurt system performance by conducting too many unnecessary email, web, background, and other scans that use too much of the systems available resources. This performance robbing becomes a big nuisance when your trying to run normal applications. The best free antivirus software programs, such as, AVAST, AVIRA, and AVG are better optimized and do not rob system performance. I have been running AVG for years now, but recently I have started evaluating AVAST and AVIRA because they are also highly rated by the community. If you check CNET’s download.com you will find that AVG still leads in the number of total downloads, but AVAST and AVIRA are coming on very strong.
I would suggest always using the free basic versions, when you can, or use the free trial antivirus version for evaluating. Sometimes McAfee, Norton, and some other big names perform too many background and other unnecessary scans that impact your system performance too much. Antivirus software is important and a good reliable program is a must to assure protection when needed without impacting system performance. Backing up important data is also a must or imaging partitions.
I use antivirus software only to alert me of an infection. Once infected I restore my operation system partition using imaging software, such as, Norton Ghost or Partimage. This allows me to completely restore my operating system and be fully operational in minutes. Windows is vulnerable to both viruses and corruptions so having a quick and easy way to restore is essential to keep me productive.