13 Best Lightweight Antivirus Software for Old PCs

Get the best antivirus solution for your old PC 👾

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
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  • 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.

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 users get attached so they continue using them.

For that, 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 NameSupported Operating SystemProcessor Requirements
ESET NOD32Windows 7, Windows 8, 8.1, Windows 10, Windows Server 2011Intel® or AMD x86-x64
BitdefenderWindows 7, Windows 8, Windows 19, Windows 11Any processor, but older ones may affect performance
TotalAVWindows XP, Windows Vista, Windows 7, Windows 8, Windows 10Intel/ AMD 1.6 GHz or faster
Panda SecurityWindows XP, Windows Vista, Windows 7, Windows 8, Windows 10Intel Pentium 300 MHz or faster
Avira AntivirusWindows 7 or newerIntel Pentium 4 / AMD Athlon 64 Processor or newer
Kaspersky Internet SecurityWindows 7 or newerIntel Pentium 1 GHz or any other faster processor
Intego360 Total SecurityWindows 7, Windows 8, Windows 10, Windows 11Any processor, but older ones may affect performance
Webroot SecureAnywhereWindows 7, Windows 8, Windows 10Intel/Pentium/Celeron/AMD or other that meet OS requirements
Avast Free AntivirusWindows 7, Windows 8, Windows 8.1, Windows 10, Windows 11Intel Pentium 4 / AMD Athlon 64 processor or faster
AVGWindows Vista, Windows 7, Windows 8, Windows 10Intel Pentium 1.5 GHz or faster
Secure APlusWindows 7, Windows 8, Windows 10, Windows 11Intel Pentium 4, 2GHz or faster
Clam AVWindows 98, Windows Me, Windows 2000, Windows XP, Windows Vista, Windows 7/8/9/10/11Any processor, but older ones may affect performance

Which free antivirus uses the least memory?

Antivirus software uses 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 NameRAM usage (MB)
Avast Free Antivirus6.3 MB
Panda Antivirus9.8 MB
BitDefender14.9 MB
Kaspersky23.4 MB
AVG29.5 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 – Good management system

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The top lightweight solution 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 demanding antivirus software.

Antiviruses are known to take a toll 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 its 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

Keep your old PC secure with ESET NOD32 Antivirus, the most lightweight and up-to-date software.
Check price Visit Website

Bitdefender – Exclusive adaptability technology

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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

TotalAV – Fast and efficient software

TotalAV is also a lightweight software that doesn’t impact your computer performance and still provides outstanding protection.

It instantly detects and blocks malicious websites and content to keep your personal data safe and secure. It also checks your downloads and executables for threats and viruses every time your PC accesses them.

TotalAV helps you encrypt your connection by leaving no digital footprints and making your activities anonymous and impossible to track.

You can easily generate strong and unique passwords for all your online accounts and keep them safe behind a vault.

Remove harmful threats from your PC and schedule smart scans to run at your set time and ensure your system remains protected at all times.


Take full advantage of TotalAV’s comprehensive protection and safeguard your PC.
Check Price Visit Website

Panda Security – Simple usage

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 in 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

Avira Antivirus – Thorough scan

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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

Lightweight and fast, Avira will protect you from current and new threats.
Get it free Visit Website

Kaspersky – User-friendly program

Kaspersky Antivirus is one of the most 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 includes 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.


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

Intego – Exceptional online threat monitoring

Intego is our second choice when it comes to world-class and lightweight antivirus programs for old computers.

It has a low-resource usage so you don’t have to worry about slowing down your device’s performance and state.

Intego can help you not only exterminate all types of cyber threats but prevent them from destroying your PC’s health as well.

It is very easy to work with because it has an intuitive user interface and offers advanced technology that keeps your old PC safe with real time monitoring.

Intego is a well-known and recommended antivirus software thanks to its excellent digital threat detection capabilities and improved security.


Improve your old PC’s security without affecting its performance by using Intego.
Free Trial Visit Website

Webroot Secure Anywhere antivirus – Impressive security tool

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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 from trying 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

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

Avast Free Antivirus – Strong secure connection

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 than Avast Free Antivirus. Moreover, it is compatible with all Windows OS.

This tool comes with features such as a 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

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

AVG – Powerful blocking feature

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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 insecure 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

SecureAPlus – Customizable interface

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

Clam AV – Multiple versions available

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

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

A lightweight antivirus is a safe solution for an old PC because it is a program specially created to take minimal impact on your computer and not slow down its performance at all.

Some of them even have advanced technology that knows when you’re gaming, for instance, and doesn’t interfere with your activity to avoid slowing down your PC.

Do share with us your experience in using any of the antiviruses for the 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 the 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.
Which is the lightest antivirus for Windows 7?

The lightest antivirus for Windows 7 is the ESET NOD32 antivirus software solution.

What is the most lightweight free antivirus?

The most lightweight free antivirus you can opt for is the Bitdefender antivirus program.

Is Windows 7 more vulnerable to viruses?

Without specialized software and security updates, Windows 7 can be prone to virus damage.

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