AVG Hall of Famer Dean Davies has written a post on his very own blog explaining why it’s not a good idea to run multiple security suites at the same time on a single PC.

Using more than one anti-virus program has been an issue for quite a number of folks that I have seen in the online forums that I’m involved in. This topic has confused a number of people that may not altogether understand how these programs work.

Problem:
Almost all security suites like AVG use a system or module that run in realtime, meaning they constantly supporting and protecting as you work, game or browse. Components like LinkScanner and AVG’s Resident Shield are two examples of realtime protection that your antivirus can offer, without these functions, the AV would simply become more of an on demand scanner service only activated when you wish to scan your PC for threats at certain times. There are obvious risks when surfing, downloading or gaming if your antivirus only protects you when you run it. Therefore security suites track things in real time to ensure you are protected.

This is where conflicts can occur between different AV products running simultaneously. As separate programs scan and analyse files at the same time, conflicts can occur possibly leaving the system unstable and potentially increasing incidences of false positives reports.

A further complication of “running” multiple antivirus products at the same time is the extra drain on system resources.

Solution:

The conflicts and instability of running several antivirus products simultaneously can be avoided by setting one of the programs to “on demand mode”. This will prevent the realtime scanners from clashing but still allow you to perform a thorough on-demand scan.

This is a great method of enhancing your security options with extra malware definitions and utilities from a range of programs. It’s just important to remember that while you can benefit from as many security programs as you like, it is advisable to only run a single realtime scanner at any given time.

Read Dean’s blog in full at here.