Antivirus software has historically been known to take up a lot of system resources which translates to less resources available to play your games. However, that's not always the case. Webroot SecureAnywhere takes up less than 800kb of space on your hard drive*, and it uses only about 5MB of RAM on average. The impact to gaming is non-existent. Compare this to the hundred of megabytes of storage space and the sometimes couple-of-hundred megs of RAM usage for bulkier antivirus programs.
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And if you think your games are safe from attack, think again. New research has found serious exploits in most major gaming engines that can be used to drop a malicious payload onto your system. When you consider that the so-called "gamer mode" in most antivirus programs simply disables your protection in order to speed up your game, what good is that so-called protection while you're gaming? The better solution is to use a program that doesn't need to be shut down while you're gaming. In other words, use Webroot SecureAnywhere, which keeps your system safe and secured with no lag, framerate drops, or nasty side effects while you're gaming.
*The executable file and program directory are smaller than 800kb.