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Will Antivirus Software Slow Down Your Devices in 2023?

Updated on: September 7, 2023
Ben Martens Ben Martens
Updated on: September 7, 2023

Short on time? Here is the best lightweight antivirus in 2023:

The best antivirus programs in 2023 shouldn’t noticeably slow down any of your devices — whether it’s on a PC, Mac, Android, iPhone, or iPad. 

Antivirus programs used to have a bad reputation for slowing down computers, but modern antivirus solutions (such as Bitdefender) include a variety of tools and features that are designed to help avoid slowdowns, such as cloud-based anti-malware engines and system optimization tools.

There are some instances where you might see slowdown from your antivirus, particularly during full disk scans. However, there are also many other reasons why your device might not be performing as fast as it once did — out-of-date software, hardware limitations, background applications, bloatware, malware, and a range of other issues can all affect your device’s performance.

Below is a comprehensive guide on the different reasons a device may slow down, what to look out for, and what you can do to improve performance. I also offer my top picks for the most lightweight antivirus solutions in 2023 that can provide excellent malware protection without slowing down your devices.

Risk-Free for 30 Days — Try Bitdefender Now 

Will Antivirus Software Slow Down Your Computer?

Most antivirus programs include a range of features to mitigate system slowdowns, but it does still happen sometimes.

It’s worth noting that antivirus programs are not one-size-fits-all — one antivirus may run well on one person’s computer, but it might not necessarily work as well on another.

For example, McAfee ran perfectly on my Windows 10 PC, but it significantly slowed down my friend’s PC.

Usually, there are logical causes behind slowdown, which may or may not be linked to your antivirus software. For instance, some antiviruses’ full disk scans can slow down your device, and some web shields and VPNs can affect your browsing speeds, but usually system slowdown is due to other factors (like malware, junk files, outdated software, or just too many programs running on your device).

If you think your antivirus might be affecting your device’s performance, or you’re worried about your system slowing down, here are some common issues to watch out for.

How to Know if Your Antivirus Is Slowing Down Your Device

Here are the most common symptoms of slowdown that can be caused by antivirus software.

Monitor System Activity

Open your Task Manager (Windows) or Activity Monitor (Mac) and check which programs are using most of your system resources — CPU, RAM, battery power, etc.

If your antivirus is using up a lot of system resources unnecessarily, especially if there isn’t a full disk scan running, then you should try to quit the antivirus software and relaunch it. If it continues to use up a lot of system resources, then you should consider uninstalling the software and installing a new antivirus.

Your Device Runs Very Slowly During Scans

Make a note of when your device is running slowly. A lot of computers experience slowdown during antivirus scans. If the scans are running for more than an hour, or your device is unusable during scans, you may want to explore changing your antivirus — or at the very least, scheduling scans for a different time.

If you’re looking for an alternative antivirus that won’t use too many system resources during malware scans, I recommend Bitdefender.

Your Device Is Very Hot

If your device is hot to the touch or the fan is especially noisy, that’s a sign the CPU is working close to its limits. Antivirus scanners can use a lot of processing power, so if overheating only occurs during antivirus scans, it’s likely your antivirus is causing the system to work harder than it can handle.

When a computer has been pushed past its capacity, it will typically shut down unexpectedly, and you can even permanently damage your hardware by running at high temperatures for too long.

Constant Device Crashing

Sometimes a device can become unresponsive or even simply turn off or restart itself. Similar to overheating, this is an indication of a computer being pushed beyond its capacity. If this is a regular occurrence during antivirus scans, it may be that your antivirus program isn’t well suited to your device’s operating system. Take a look at my list of recommended lightweight antivirus software to try something less CPU intensive.

Other Reasons Why Your Computer Might Be Slow

Your antivirus may not be the only reason your device’s performance is lagging. A variety of factors can impact system speed — below are a few of the most common reasons behind a computer’s performance issues.

  • Cryptojackers, spyware, and malware. Malware infections — like trojans, cryptojackers, and spyware — are one of the main culprits for a device’s poor performance. Malware can consume a significant amount of device memory and cause damage to programs and files. Cryptojackers and spyware both run passively on systems, meaning a device can be infected for months or even years without the user knowing that their system is compromised.
  • Outdated software. Software updates generally include security and performance patches that are necessary to run your programs as safely and effectively as possible. Failing to regularly update software will result in buggy, slow programs, as well as exposing software vulnerabilities that can be exploited by hackers.
  • Too many background apps running. When a computer attempts to load and run countless applications at once, the system will become sluggish. Use the Task Manager and Activity Monitor to check which programs are taking up the most processing power on your device, and make sure to fully close apps when you’re not using them.
  • Too many programs run on startup. If you have too many programs trying to open when your computer is booting up, this can place a lot of stress on your computer and slow down your boot sequence.
  • Your computer’s fan is clogged. Without a properly functioning fan, a device can’t cool down, which can cause unexpected crashes. Sometimes your fan can become clogged with dust and needs to be cleaned (preferably by a specialist if you’re not confident with computer hardware). Your fan might even be broken and needs to be replaced.

How to Choose a Fast & Lightweight Antivirus (That Won’t Slow Down Your Device)

  • Effective real-time malware protection. You should use an antivirus with real-time protection, which constantly scans for viruses, malware, and other online threats to detect and stop them before they can infect your device. This means you won’t need to run as many full disk scans — making the antivirus software less CPU intensive.
  • Cloud-based scanning. Cloud-based scanners use remote servers to run scans and analyze your drive, reducing the impact on your device’s performance.
  • File caching. Smart antiviruses cache (i.e. remember) the files from every scan, marking files as safe and instructing the program to skip them in future scans. This significantly decreases the amount of time and processing a scan requires.
  • Scans scheduling. Your antivirus should include scan scheduling, which enables you to run CPU-intensive full system scans while you’re not using your computer, so you’re less likely to experience system slowdowns.
  • System tune-up tools. System optimization tools are designed to clean and speed up your system, by removing junk files, optimizing your boot sequence, flagging out-of-date software, optimizing your CPU for gaming, and more.
  • Frequent updates. The best antivirus programs are updated frequently to optimize the application’s performance, fix bugs, and apply security patches. If your antivirus software isn’t frequently releasing updates, chances are it’s not going to be as effective against malware threats, or as efficient on your device.

3 Best Antiviruses That Won’t Slow Down Your Device in 2023

Quick summary of the best lightweight antiviruses in 2023:

  • 🥇 1. Bitdefender — Best lightweight antivirus in 2023.
  • 🥈 2. Avira — Easy-to-use antivirus with system optimization tools.
  • 🥉 3. Intego — Best Mac antivirus with fast system scanning.

🥇1. Bitdefender — Best Lightweight Antivirus in 2023

Quick summary of the best lightweight antiviruses in 2023:

Bitdefender is a lightweight but powerful antivirus with top-notch malware detection and a ton of good additional features.

Its cloud-based malware scanner uses machine learning together with signature-based scanning technology, and it’s one of the best on the market. It’s fast, it doesn’t cause any slowdown, and it detected 100% of the malware files during our stress-testing.

Bitdefender’s full disk scan also used less than 2% of my device’s memory during my tests, meaning I could easily perform activities like streaming HD video and playing games without any slowdown.

Aside from effective malware protection, Bitdefender offers:

  • Real-time malware scanning.
  • Proactive ransomware protection.
  • System clean-up tools.
  • Ransomware remediation.
  • Web security.
  • And more…

Bitdefender has a good system optimization tool, called OneClick Optimizer, which scans your system and removes unnecessary files from your device. As with the antivirus scan, the OneClick Optimizer only takes a few minutes and frees up a substantial amount of unnecessary bloat from your PC to help improve performance.

Overall, Bitdefender is an excellent all-in-one solution that provides flawless malware protection, doesn’t take up unnecessary amounts of processing power, and will keep your device running smoothly without interruption. Bitdefender’s plans start at just $14.99 / year, and they all come with a 30-day money-back guarantee.

Try Bitdefender Now

Read the full Bitdefender review here >

🥈2. Avira — Best Antivirus with System Optimization + Great Free Plan

Quick summary of the best lightweight antiviruses in 2023:

Avira’s anti-malware engine is one of the most powerful on the market, and it also offers some excellent system tune-up options. Its malware scanner uses cloud-based technology, which keeps its impact on computer performance at a minimum and prevents the software from slowing down your device.

The malware scanner scored an excellent detection rating during my tests, and the web protection extension managed to block all of the phishing and malicious sites I attempted to access.

Avira’s comprehensive internet security suite includes:

  • Malware scanner.
  • Real-time protection.
  • Web protection.
  • System optimization tools.
  • Hard drive clean-up tools.
  • VPN (virtual private network).
  • And more…

Its performance optimization tools are also great — they can optimize your systems’s startup speed, clear out junk files, scan for out-of-date software, clean out your browser’s cached files, and more. While most of Avira’s system optimization tools are easy-to-use, even more advanced tools can be found in Avira’s System Speedup Pro app — great for users who want to access more system optimization settings.

Avira’s free plan even includes web protection, a password manager, a VPN, and other features that no other antivirus provider offers for free in 2023. But for full access to all of Avira’s features, including the system speedup tools, you’ll need to try Avira’s Prime package ($59.99 / year). Avira’s yearly plans come with a 60-day money-back guarantee (but monthly plans only have a 14-day money-back guarantee).

Try Avira Now

Read the full Avira review here >

🥉3. Intego — Best Lightweight Antivirus for Mac in 2023

Quick summary of the best lightweight antiviruses in 2023:

Intego is my favorite antivirus for Macs — it’s fast, easy-to-use, has excellent malware detection capabilities, and comes with a range of additional tools that improve upon Apple’s built-in security settings.

During my tests, Intego’s malware scans were incredibly fast — the malware scanner uses file caching technology to skip over previously scanned files marked as safe (something which Bitdefender doesn’t include). File caching significantly reduces scan times and impact on system performance. The initial full system scan took 1 hour and 40 minutes to scan over 800,000 files, but subsequent scans took just over 10 minutes.

To specifically help avoid any slowdown caused by its scans, Intego also has a “Scan with low priority” option, which prioritizes CPU power for other programs running at the same time as a virus scan. This means the scan will take longer, but it reduces any potential slowdown.

Intego also includes an excellent set of device optimization tools that help prevent slowdown and enhance performance by removing clutter on your device:

  • Reclaim. Scans and removes unnecessary junk files, including logs, caches, trash, and downloads.
  • Duplicates. Scans for duplicate files taking up precious disk space.
  • Organize. Enables easy organization of all folders and apps on your Mac.

Intego also comes a great range of extra features, including an excellent smart firewall, a robust set of parental controls, and a backup feature — all of which are major improvements on macOS’s own built-in features.

Intego’s Mac Internet Security X9 ($19.99 / year) includes the antivirus scanner and smart firewall. But to get access to system optimization tools, parental controls, and backup features, you’ll need to try the Mac Premium Bundle X9, which starts at just $34.99 / year. Intego also offers a 30-day money-back guarantee on all of its plans.

Try Intego Now

Read the full Intego review here >

Will Mobile Antivirus Apps Slow Down Your Android or iOS Device?

Buggy mobile antivirus apps can slow down both Android and iOS devices. There are also plenty of bad mobile antivirus scanners that can put a huge strain on your battery, so it’s always best to use a trusted Android antivirus app or iOS security app.

However, there are usually other reasons why your mobile device is slow, including:

  • Malware. It’s exceptionally rare for iOS devices to get malware, but Android-specific malware is a major threat in 2023. Mobile malware is an issue for your privacy and safety, but also for your phone’s performance, so it’s important to install a mobile security app, like Norton Mobile Security.
  • Too many files or apps. If you have too many files or apps (especially memory-intensive games or social media apps) on your device, you’re going to experience performance issues.
  • Out-of-date software. If you ignore your operating system’s updates, your phone won’t perform optimally and will be more vulnerable to online threats. Make sure you install all updates when they become available.
  • Buggy apps. Apps can be buggy and have a negative impact on your mobile device’s performance. If you’ve recently noticed changes in your device’s performance, check for recently installed apps and remove any you suspect of slowing your device.

How Can You Speed Up Your Computer & Mobile Devices?

It’s usually easy to get your devices working at their best again when you know what to do.

Below are my top tips for how to speed up your various devices — and for even more tips on speeding up your PC, check out our 20 Easy Ways to Speed Up & Clean Your PC blog post.

How to Speed Up Your PC or Mac

  • Limit the number of startup programs. Too many programs launching when you boot up your computer will affect your startup speeds, so try to keep the number of programs that launch during startup to a minimum.
  • Uninstall unused and unnecessary programs. Routinely audit what programs are installed on your computer, and uninstall those that you don’t use. By removing what you don’t use or need, you’ll free up memory on your computer which allows for faster processing speeds. Avira’s Prime’s application uninstaller helps with this — it lists all of the software installed on your computer and enables you to easily remove multiple applications at once.
  • Maintain your device. Make sure your computer’s software is up to date and the hardware is maintained. This includes cleaning your fan regularly using compressed air, periodically defragmenting your hard drive, and using external storage if/when your hard disk fills up.
  • Change your antivirus. If your computer is running very slowly during antivirus scans, or if your antivirus software is using a lot of system resources unnecessarily, you need to switch to a quality, lightweight antivirus (like Bitdefender) that won’t slow down your computer.

How to Speed Up Your Mobile Devices (Smartphone or Tablet)

  • Install software updates. Software updates include important fixes, including performance improvements, that can significantly improve your device’s performance. Whenever a software update becomes available, you should install it as soon as possible.
  • Uninstall unused and unnecessary apps. Regularly audit the apps you have installed on your mobile and remove the ones you don’t use. Unused apps can take up a surprising amount of space on your device, and less space generally means slower performance.
  • Install a good mobile security app. Such an app can better your device’s performance by identifying and removing malware, bloatware, junk files, and other elements that may be slowing it down. Additionally, it provides protection against potential online threats.
  • Free up memory. If you’re constantly running out of mobile storage space, consider using cloud storage for media files or, depending on the device, purchasing an SSD card as removable storage. Auto-deleting texts and disabling automatic media downloads on messaging apps will also help greatly in decreasing the memory used.

Bottom Line

A decent antivirus shouldn’t be causing your device to slow down in 2023. The best antiviruses include features like advanced cloud-based scanners, smart scanning technology, scan scheduling, low-impact quick scans, and more, making it possible to keep your devices fully protected without causing significant slowdowns.

Several factors could be slowing down your device, such as malware, outdated software, an excessive number of apps, or aging hardware. A good antivirus can effectively address all of these problems.

My top lightweight antivirus choices are Bitdefender for PCs and Intego for Macs. Both are great overall antivirus solutions that keep your computer protected against the most current malware threats, help you to keep your device optimized, and don’t use up system resources unnecessarily.

Frequently Asked Questions

Can antivirus software slow down your devices in 2023?

Antivirus software might slow down your system while performing a full disk scan, but things like lightweight scanners, flexible scan scheduling features, and system optimizers can minimize slowdown on your device.

Antivirus programs with cloud-based scanners, such as Bitdefender, run their scans externally to your device which means you won’t experience slowdown, even during a full disk scan.

But remember that slowdown can also be caused by other issues on your device. Malware infections, out-of-date software, insufficient hardware, and an excessive amount of background programs running may all factor into why your device is experiencing sluggish performance. Top antivirus suites, such as Bitdefender, have a wide range of tools that can find and fix the majority of issues that might be affecting your device’s performance.

What is the fastest antivirus program available for Windows?

Bitdefender is the fastest antivirus for PC users. Because Bitdefender uses cloud-based technology, the anti-malware scanner doesn’t use a computer’s own resources when scanning. This results in quick scans that cause no interruptions to the device’s performance.

In addition to being lightweight, Bitdefender is one of the best antivirus suites on the market. It has an excellent malware-detection rate, is easy to use, and is cost-effective, making it a great choice.

What is the fastest antivirus program available for Mac?

Intego is my #1 antivirus choice for Mac users — it’s secure, lightweight, and comes with some great additional tune-up features.

Intego uses file caching technology, which marks files as safe after the initial scan. So while the first scan can take a while (over an hour), subsequent scans will usually be as short as 10–15 minutes.

How can I improve the performance of my device?

System optimization tools are great ways to improve a device’s performance, and luckily, most good antivirus programs will include some. Both Bitdefender and Intego come with excellent optimization tools that are easy to use and effective at removing junk files and programs in order to improve your system’s performance.

There are a lot of easy ways to improve your device’s performance — it’s important to keep your system’s OS up to date, and to routinely audit the programs and apps installed on your device and remove unused applications. Purchasing external storage (i.e. a physical external hard drive or cloud storage) can also help remove the burden on your local hard disk, which will in turn speed up your device.

How do I monitor my device’s performance?

For PC users, right-click on the Start menu or press Ctrl+Alt+Delete and select the Task Manager. The Processes tab will list all the applications currently running, alongside how much CPU power and memory they are each using. The Performance tab provides a live graphical depiction of your CPU’s performance.

For Mac users, click on the search icon in the top right corner and type in “Activity Monitor” to bring up the application. You can see both CPU and memory usage for each application, and quit those that don’t need to be running.

If you notice any programs that are using up a lot of system resources, then you should try to quit them if you don’t need them. If your antivirus software is using up system resources unnecessarily, even though no full disk scans are running, then you should consider uninstalling the software and trying an alternative antivirus.

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About the Author
Ben Martens
Ben Martens
Senior Editor
Updated on: September 7, 2023

About the Author

Ben Martens is a cybersecurity journalist with a background in internet ethics, malware testing, and public policy. He resides in Oregon, and when he's not advocating for the rights of internet users, he's walking with his dog and inventing stories with his daughter.