12 Best Lightweight Antivirus Software for Old PCs

by Ivan Jenic
Ivan Jenic
Ivan Jenic
Troubleshooting Expert
Passionate about all elements related to Windows and combined with his innate curiosity, Ivan has delved deep into understanding this operating system, with a specialization in drivers and... read more
Affiliate Disclosure
  • Older PCs have special requirements when it comes to antivirus tools, such as low CPU power.
  • They also have lower memory space, so it's important to get an AV with a small file.
  • Because of that, we've compiled a list of the best premium antivirus tools for old PCs.
  • If you want to try out the software before you buy them, know that many include free trials.
lightweight antivirus for old pc
ESET Antivirus comes with all the security tools that you may ever need to protect your data and privacy, including:

  • Anti-theft support
  • Webcam protection
  • Intuitive setup and UI
  • Multi-platform support
  • Banking-level encryption
  • Low system requirements
  • Advanced anti-malware protection

An antivirus program needs to be fast, efficient, and cost-effective, and this one has them all.

If you are still keen on using older devices, you need to use a lightweight antivirus for your old PC.

Antivirus software has become vital in this age of web surfing as computers need protection from Internet-based malware and other offline threats.

This can pose problems with PC users of older Windows OS such as Windows Vista, Windows XP, Windows 2000, Windows NT, etc. However, there’s still antivirus software for Windows XP Service Pack 3.

Although the obvious choice should be to replace such PCs, sometimes people get attached to them more closely than other devices with years of data stored.

So they keep their old PCs and continue using it. The best antivirus for older computers should have minimal system and hardware requirements.

However, most of the latest editions of popular antivirus may not run properly due to the PC’s outdated specs.

Meanwhile, we have compiled some of the best antiviruses that run efficiently on older PCs with a focus on their functionality and effectiveness.

Why do you need a lightweight antivirus for an old pc?

Older PCs have lower RAM memory and disk space as well as slower processors, so it is important to use a light antivirus utility to protect them.

Antiviruses that have a smaller footprint on your system let you use other apps while scanning. You can leave them in the background without worrying about interruptions.

Here are some of the key benefits of a lightweight antivirus:

➡️ Requires less disk space and installs faster

➡️ Can run in the background without slowing down your PC

➡️ Uses less CPU and memory when running scans

➡️ Stays up-to-date without taking a toll on your resources

Best lightweight antivirus software for Windows old pc (Windows XP, Vista, 7, 8/8.1, 10)

Antivirus Name Supported Operating System Processor Requirements
ESET NOD32 Windows 7, Windows 8, 8.1, Windows 10, Windows Server 2011 Intel® or AMD x86-x64
Avira Antivirus Windows 7 or newer Intel Pentium 4 / AMD Athlon 64 Processor or newer
Kaspersky Internet Security Windows 7 or newer Intel Pentium 1 GHz or any other faster processo
360 Total Security Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10 Intel/ AMD 1.6 GHz or faster
Webroot SecureAnywhere Windows 7, Windows 8, Windows 10 Intel/Pentium/Celeron/AMD or other that meet OS requirements
Avast Free Antivirus Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11 Intel Pentium 4 / AMD Athlon 64 processor or faster
Bitdefender Windows 7, Windows 8, Windows 19, Windows 11 Any processor, but older ones may affect performance
AVG Windows Vista, Windows 7, Windows 8, Windows 10 Intel Pentium 1.5 GHz or faster
Panda Security Windows XP, Windows Vista, Widnows 7, Windows 8, Windows 10 Intel Pentium 300 MHz or faster
Secure APlus Windows 7, Windows 8, Windows 10, Windows 11 Intel Pentium 4, 2GHz or faster
BullGuard Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10 Any processor, but older ones may affect performance
Clam AV Windows 98, Windows Me, Windows 2000, Windows XP, Windows Vista, Windows 7/8/9/10/11 Any processor, but older ones may affect performance

Which free antivirus uses the least memory?

Antivirus software use memory differently depending on the tasks they employ. Most antiviruses are left to run in the background to detect real-time threats.

That is the idle memory usage and is pretty low for most antiviruses. They may use more memory when performing regular full PC scans or full scans.

Many users say that free antivirus software does use up more memory space, but there are some utilities that are not as demanding as others:

Antivirus Name RAM usage (MB)
Avast Free Antivirus 6.3 MB
Panda Antivirus 9.8 MB
BitDefender 14.9 MB
Kaspersky 23.4 MB
AVG 29.5 MB

RAM usage rates vary, but these are the medium values that have been found when running a regular PC scan.

Which is the best antivirus for old PCs that I can get?

ESET NOD32 Antivirus

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The top lightweight solutin on the market for low-end PCs is ESET NOD32. When it comes to resource consumption, an older PC might not hold up with the stress caused by a demanding antivirus software.

Antiviruses are known to take a tool on the system they’re installed in, especially when doing thorough scans.

Thankfully, ESET is able to manage your system, protect it, remove malware, and perform periodic scans without affecting it’s performance.

The Advanced memory scanner feature will decrypt, analyze files and monitor malicious behavior through a specialized algorithm that doesn’t sacrifice CPU power to run.

ESET NOD32 Antivirus

ESET NOD32 Antivirus

Keep your old PC secure with ESET NOD32 Antivirus, the most lightweight and up to date software.

Check priceVisit website

Avira Antivirus

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Another great and free option on our list is Avira. The software performs very well on older PCs,and it’s proven to be one of the best antiviruses currently.

You will be able to perform thorough scans of your computer without encountering any problems. Besides that, Avira can also help improve your PC’s performance by removing unwanted files.

The antivirus has both a full scan and quick scan feature and is always running in the background to stop incoming attacks.

The file remover will clean your PC of unnecessary junk files and bloatware and make it run faster.

Avira will also protect you from suspicious websites and keep your identity private. To top it all off, it also includes a free VPN for extra safety.

The VPN can protect your online activity, making for more secure payments and personal data sharing.

Avira Antivirus

Avira Antivirus

Lightweight and fast, Avira will protect you from current and new threats.

Get it freeVisit website

Kaspersky Internet Security

antivirus old pc

Kaspersky Antivirus is one of the widely used antivirus software in the world which gives protection against malware.

The Antivirus uses a layered defense posture to scan your system quickly without giving false positives.

It is also compatible with older versions of Windows OS including Windows XP and Vista which makes it a good choice for users with older PCs.

This program include file scanners, software uninstallers, gamers’ mode, ransomware decrypter, system restore, virtual keyboard, cloud protection, browser configuration, rescue disk, etc.

In addition, one of the unique features of Kaspersky is that it requires 512mb Ram and 480mb disk space to run.

This makes it a great option for older PCs especially PCs which have 1GB Ram and slower processors.

Kaspersky Internet Security

Kaspersky Internet Security

Award-winning security from a well-known provider in the security field for over 20 years.

Check priceVisit website

360 Total Security

antivirus software for old PCs

This software is efficient especially on old PCs so as to give protection against viruses, malware and Trojans.

360 Total Security has the unique advantage of being compatible with all versions of Windows from Windows XP to Windows 10.

This program offers three major protection features which include Internet browsing, Privacy, and System Protection.

This makes it an attractive security tool for older PCs as it would install properly while giving premium functionality and protection.

However, this antivirus utilizes a lot of PC resources, especially when conducting full scans and trying to do other things with the PC.

There is a distinct reduction in system performance for laptops not having more than 1.5 GB of free memory.

360 Total Security

360 Total Security

Older PCs need special kind of care in terms of what antiviruses can provided, and 360 Total Security can offer it.

Check priceVisit website

Webroot Secure Anywhere antivirus

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Next, Webroot Secure Anywhere is a web-based antivirus for your old PC.

This antivirus incorporates premium security features in a tiny little package; hence, few computer resources are utilized while providing excellent protection to your old computer.

The tool protects you against web attacks with a strong firewall, as well as web filtering. This stops hackers that try to steal your data.

This antivirus has other impressive Internet security tools, as well as a high detection rate for all sorts of threats including ransomware and malware.

The activation adds a password manager as well. In addition, this tool has very good detection rates for malware and virus threats with anti-phishing features.

Webroot Secure Anywhere

Webroot Secure Anywhere

Give your old PC a modern-day antivirus to protect it. Choose Webroot as your go-to security system!

Check priceDownload now

Avast Free Antivirus

antivirus old pc

Avast is a worldwide giant in the antivirus industry with hundreds of millions of users worldwide.

If you want an efficient antivirus for your old PC, look no further with Avast Free Antivirus. Moreover, it is compatible with all Windows OS.

This tool comes with features such as file scanner, Windows Explorer context menu integration, Rescue Disk, password manager, junk file cleaner, Wi-Fi inspector, Game Mode, and browser cleaner.

The Wi-Fi inspector ensures that you have a secure connection even when connecting to a public network.

When you activate the Game mode, certain notifications and pop-ups will be temporarily disabled so you will not be interrupted.

In addition, Avast Free Antivirus comes with web, behavior, and mail shields. You can download the software from the official website.

Avast Free Antivirus

Avast Free Antivirus

Protect your outdated PC with Avast Free Antivirus, one of the best lightweight apps on the market!

Free downloadVisit website


antivirus old pc

Next, we have a tool that has been on the market for a long time. Bitdefender Internet Security is well known for its powerful capabilities to detect, block, and remove cyber threats.

It is built by a strong development team that aims to offer comprehensive protection. Its detection mechanism does not use too many system resources, so it is suitable for older PCs as well.

It uses Bitdefender Photon which is an exclusive technology that makes the software adapt to your system hardware and software configuration. It saves resources and improves performance and speed rates.

Bitdefender uses machine learning to detect suspicious behavior in your system It also has a strong database that is constantly updated with current information about the newest threats.

The tool has a powerful vulnerability assessment feature that can be very useful for users of older PCs. It identifies outdated or unsecured software, missing security patches, and other holes that can lead to infection.

With this antivirus, you get complete protection against all the cyber threats of today. It protects against viruses, malware, ransomware, phishing attacks, fraud attacks, and more.

BitDefender Internet Security

Equip your PC with a powerful security software that protects you on all fronts without requiring too many resources.

Free trial Visit website


windows vista antivirus

AVG is a full-featured antivirus utility. It is capable to offer well-rounded protection against all cyber threats.

This antivirus can detect and remove well-known threats as well as new, emerging ones. It blocks suspicious activity that could signal an infection.

It blocks unsecure downloads and email attachments, ransomware, spyware, viruses, and other types of malware.

If you use an older PC, this antivirus can be of help. Not only is it lightweight, but it also has a performance scanner feature.

It lets you know whether there are any faulty settings or outdated apps that slow down your PC.

AVG performs well on PCs with lower memory, even when scanning or installing updates.

The premium version of the software has added benefits such as an Enhanced Firewall and 24/7 customer support.


Protect and optimize your PC’s performance with this up-to-date antivirus.

Free trial Visit website

Panda Security

Panda Security is known for its pleasant user experience. It has a simple application with intuitive options.

The tool is light but strong in terms of protection capabilities. It is fast responding with real-time antivirus and anti-malware alerts.

It has low resource usage when running it the background and does not take up too much memory space when scanning either.

The antivirus can block online cyberattacks with its strong Firewall that can run alongside the Windows built-in Firewall.

Along with that, it includes a VPN that enables you to have a more secure online experience. It can help protect sensitive data such as your location, bank information, and identity.

Panda is great if you use older OS versions.It works on Windows operating systems starting with Windows XP 32-bit.

Panda Antivirus

Don’t compromise between security and performance and enjoy real-time protection with minimal system requirements.

Free trial Visit website


This is a web-based antivirus program that combines major antivirus programs together. SecureAPlus is ideal antivirus software for users of old PCs that can decide on an antivirus.

In addition, it gives access to multiple antivirus engines. As it is mostly cloud-based it does not put much stress on your computer’s resources.

SecureAplus gives you the opportunity to test the products with features such as real-time protection, detection ratio, firewall, anti-phishing, scan speed, and resource consumption.

However, SecureAPlus is cloud-based and integrates 12 popular antivirus engines into one with a customizable interface for trusted programs.

The antivirus engines include AVG, Avira, BitDefender, ClamWin, ESET, Emsisoft, McAfee, Microsoft Security Essentials, Norman, Quick Heal, Sophos, and Total Defense.

Get SecureAPlus


router antivirus

Independent tests have shown that BullGuard is capable of detecting a wide variety of malware.

The antivirus relies on virus signatures to detect existing known threats. It also provides behavior analysis that manages to block any suspicious activity from the software running on your computer.

This is part of their multi-layered protection approach. Other layers include a spam filter, backup capabilities, and more.

More proof that Bullguard cares about performance is the addition of Game Booster – an award-winning tool that blocks interruptions.

While you might not be using your computer to play games, it just goes to show that BullGuard is the right choice.

With a clean design, it’s very easy to use and lightweight enough. It requires a minimum of only 1GB RAM and is compatible with Windows 10.

Get Bullguard

Clam AV

Up next we have an open-source antivirus that is capable to run quick scans without impacting PC performance.

It is a cross-platform antivirus software with a very small file. It supports both 32-bit and 64-bit builds for Windows.

It is a command-line antivirus, but it also has a dedicated application for Windows users. Both are completely free and open-source.
The benefit of this software is that it gets more frequent updates. This means that it is able to detect and block new threats with high accuracy.

The tool has multiple versions available, you can select your preferred option when you download it.

Clam AV is able to protect your email with built-in support for all email file types. It also scans files and apps and does not let you start them until it’s clear they are secure.

This antivirus is for the most part used for its file scanning and email protection capabilities. 

Despite the fact that it is able to detect and remove PC malware, it specializes in that area.

It can thoroughly scan all major document file formats including PDF, HTML, and DOCX.

Get Clam AV

Do share with us your experience in using any of the antiviruses for old PC which we mentioned above. We do appreciate your feedback when you comment below.

Please keep in mind that these tools are also recommended for the following use cases:

  • Antivirus for very old PC – Some of the tools have such low system requirements, that they qualify as very old computers.
  • Best antivirus for old slow XP PC – Some really old PCs keep using Windows XP. While the OS is not recommended, take a look at antivirus for Windows XP.
  • Best free antivirus for old laptop – Some of the solutions presented also offers a free version that has limited functionality. You could use that before upgrading to the premium edition.
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Frequently Asked Questions

  • A computer should not have multiple antiviruses software running simultaneously. Remove the current antivirus first, and turn on the new one. Use a third-party uninstaller in case of issues.

  • Any piece of software that runs continuously will slow down the PC a bit. By how much? It really depends on the software. Some solutions are more lightweight than others. Check our top lightweight protection tools.

  • Only one antivirus should be up and running. This is true for any computer, new or old. One good antivirus is enough to get the job done.

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