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Antivirus software is important on Windows, but it can slow down your computer. The on-access scanning that protects you from malware means your antivirus has to scan every file you access before it actually opens. Luckily, there are a variety of ways to speed things up without losing security.
Heavy antivirus programs can slow down a computer – particularly an older computer running an older, poorly optimized security suite. Norton and McAfee were some of the worst offenders, but have improved with recent versions. Making sure to configure an up-to-date antivirus is one of the most important things you can do.
Antivirus applications normally scan every file you access before allowing them to open. If you have files that you consistently access, such as virtual machines, you can exclude them. Your antivirus will ignore any excluded files, allowing them to open without any scanning.
For most files, exclusions won’t offer very large speed-ups. However, for large files or lots of little files, especially ones that change frequently, exclusions may help. If you exclude your virtual machine directories, you may see a significant performance boost in your virtual machine performance.
Note that exclusions can be potentially dangerous. If you exclude your entire C:\ drive or exclude all .exe files, you may as well not be using an antivirus at all. Be smart about the exclusions you configure. For example, you wouldn’t want to exclude your Downloads directory.
To configure exclusions on Microsoft Security Essentials in Windows 7 or Windows Defender in Windows 8, open the application and click the Settings tab. You can exclude specific files or folders, exclude all files with a specific files extension, or exclude processes with a certain name.
For example, if you want to exclude your virtual machine folder, select Excluded files and locations, click the Browse button, and select your virtual machine folder. An antivirus application can’t protect against viruses inside a virtual machine, anyway – it can’t “see into” the virtual machine.
Use Gaming Mode
Some antivirus applications offer a “gaming mode” toggle, but this won’t increase your performance as much as you might think. “Gaming mode” generally disables notifications and other pop-ups so they won’t bother you while you’re playing a game or watching a movie. That’s why this feature may also be called “silent mode.”
However, gaming mode does have some benefits. While in gaming mode, antivirus applications will usually delay scheduled scans and automatic updates.
Some antivirus applications may try to automatically enable gaming mode when you have games open. For example, Bitdefender will automatically enable gaming mode when you’re playing games it recognizes, but you can also enable it manually by right-clicking the Bitdefender system tray icon and selecting Turn Game Mode On.
Tune Your Scan Schedule
Antivirus applications are usually set to perform automatic, scheduled scans. These scheduled scans can occur while you’re using your computer, slowing things down.
You can generally choose a scheduled-scan time from within your antivirus application. For example, you’ll find these options under Scheduled scan on the Settings tab in Microsoft Security Essentials (or Windows Defender on Windows 8).
By default, Microsoft Security Essentials is set to run a quick scan on Sunday at 2 a.m.. It will run only if you’re not using your computer and limit the CPU usage during the scan, so it won’t slow things down too much. However, other antivirus applications may not be so considerate. Check the scheduled scan options in your antivirus to find out.
Exclude Removable Drives
Some antivirus applications automatically start scanning USB drives, CDs, and DVDs when you insert them into your computer. The entire-drive scanning feature can help you identify drives that have malware on them, but it also makes you wait before you can use the drives at full-speed.
This option is often located in the same place as the Exclusions settings in your antivirus program. If you don’t see these options, your antivirus may not have this feature (Microsoft Security Essentials doesn’t have this feature enabled by default).
Your antivirus will still check files that you open from the removable drive as they’re accessed. However, it won’t scan the entire drive when it’s inserted.
Choose On-Access Scan Settings
More heavyweight antivirus applications may have a setting that controls how much system resources their on-demand (also known as real-time) scanning software uses. For example, in Bitdefender, you can select Aggressive, Normal, or Permissive on-access scanning. The more aggressive options take more system resources.
You may also be able to control more detailed settings, such as choosing whether or not your antivirus scans inside zip files and other archives. This takes more system resources.
Focus On Your System Drive
When performing full-system scans, you may want to focus on scanning your system drive and scanning other drives less frequently. For example, if you have a 2 TB drive full of media files – especially an external one that takes longer to access – you may want to prevent your antivirus from performing long scans on it.
Assuming you don’t store programs on the secondary drive, you shouldn’t need to scan it as frequently. If malware does make its way onto the drive, your antivirus should protect you if you ever try to open it.
Your system drive – almost always the C:\ drive – is the most important location to scan.
Use a Lightweight Antivirus
This is the most controversial advice here. Antivirus providers are constantly trying to sell us more feature-packed, do-everything solutions. However, you don’t necessarily need an Internet security program packed with everything but the kitchen sink. Internet security suites often include firewalls and phishing filters, but Windows includes a firewall and all modern browsers (even Internet Explorer) include their own phishing filters.
If your antivirus is weighing your computer down, you should consider looking at a more lightweight, speedy solution. I’ve long loved the free Microsoft Security Essentials – available for Windows 7 and included on Windows 8. It doesn’t do everything, doesn’t slow down your system, and doesn’t try to up-sell you to a paid antivirus product. However, Microsoft Security Essentials has taken a bit of a beating in some antivirus tests recently and Matt has recommended using another antivirus product instead of Microsoft Security Essentials. On the other hand, real-world test results for Microsoft Security Essentials have been fairly good.
Either way, I still use – and like – Microsoft Security Essentials (Windows Defender on Windows 8). Your mileage may vary, and that’s okay.
You could also disable on-demand scanning (also known as real-time scanning) and manually scan files when you download them. However, we don’t recommend this. It won’t help protect you against malware that arrives via security vulnerabilities, such as the security holes in Java and flaws in other browser plugins like Flash. Better safe than sorry – particularly since a well-configured, speedy antivirus won’t noticeably slow down your PC.
What other tips do you have to configure antivirus so that it doesn’t slow down your computer without giving up on security? Leave a comment and share them!