Microsoft Security Essentials vs Avira vs avast! vs AVG: Best free anti-virus/anti-malware program for Windows [3rd Edition]

Without a doubt one of the most popular questions I am asked is “which security software should I use for my computer?” Often times the person asking me the question is looking for a free security solution as opposed to a paid one. To address this question, I have already created a post on best security software. However, now – in this article – I am going to directly address the issue of “should I use Avira, avast!, or AVG?” Of course there are many other free anti-virus/anti-malware software. However, I feel these three are the most popular and most commonly inquired about, hence why I picked them.

Update on December 3, 2010: Because of its growing popularity, and requests made to me by many people, Microsoft Security Essentials is now included in this comparison.

When evaluating security software and trying to decide which one you want to use, there are two main areas which you should look at: Features and performance. So, lets get started.

This review is part of our Best Free Windows Software section. Check out more articles on the best free Windows programs from here.

Table of Contents
Summary of Update
Features Comparison
Performance Comparison

Detection Rates
Malware Removal Effectiveness
Computer Impact

Final Verdict
Download Links

Summary of Update

In the 3rd edition of dotTech’s guide on Best Free Windows Anti-Virus/Anti-Malware the following changes have been made:

• Features Comparisonsection has been updated to reflect new features added to Avira Free, avast! Free, AVG Free, and Microsoft Security Essentials since the 2nd edition of this article was written. All four made tweaks and modifications to their existing features; the major new features are:
  • Avira Free – “WebGuard”
  • avast! Free – Behavior blocker, “Auto Sandbox”, “Script Shield”, “WebRep”
  • AVG Free – Largely unchanged
  • Microsoft Security Essentials – Behavior blocker, “Network Inspection System”

• Performance Comparison section has been updated to reflect new on-demand and retrospective detection rates for Avira Free, avast! Free, and Microsoft Security Essentials. AVG Free did not participate in the latest retrospective tests so AVG Free’s detection rates have been updated only for on-demand tests.
• Performance Comparison’s sub-section Speed and Computer Usage has been rewritten with a new source and renamed to Computer Impact.
• Performance Comparison now includes a new sub-section, Malware Removal Effectiveness.

Features Comparison

(Click on the chart to view it in full size.)

In terms of features, as you can see in the chart above, all four programs provide the necessary fundamental protection. However, it is worth noting that neither of the programs provide full/advanced phishing protection; you will have to cough up money for paid versions to get full/advanced phishing protection. Or, you could just be careful about what links you click; and double-check to make sure the website you are at is who it claims to be since phishing success heavily depends on social engineering and user ambivalence.

Furthermore, while all four programs provide the fundamentals, avast! is the most notable one for going “above and beyond” the basics and providing a little extra bang for the buck (or lack thereof). In other words, avast! provides more “extra” features than the other three, although AVG Free also has some nice extras. It also should be noted Avira Free’s “WebGuard” requires users to install Avira Toolbar, which is powered by Ask.com; and Microsoft Security Essentials has an interesting feature called “Network Inspection System” — a guard against network-based exploits.

Lastly, even though Microsoft Security Essentials is the only one to not prompt users with advertisements it must be noted that the ads in avast! Free are non-intrusive and embedded within the main console window – they are not the popup ads Avira Free is notorious for and AVG Free sometimes displays.

Performance Comparison

Detection Rates

(Click on the chart to view it in full size.)

(Click on the chart to view it in full size.)

When viewing the above test results, keep a few things in mind:

• The On-Demand Anti-Malware Tests are tests done on the security software with all their features enabled (with all settings set to the highest possible). The Retrospective/Proactive Anti-Malware Tests are tests done specifically on the security softwares’ heuristics capabilities; their capabilities to protect against unknown/new malware that have no signatures. It needs to be mentioned that heuristics is not the only feature that security software use against unknown/new malware. Other feature, such as behavior blocking, also help detect unknown/new malware; however only the heuristics feature (and no other features, such as behavior blocking) was tested in the Retrospective/Proactive Anti-Malware Tests.
• For the The On-Demand Anti-Malware Tests
  • Microsoft Security Essentials had “very few” false positives; Avira had “few” false positives; avast! had “few” false positives; and AVG had “many” false positives.
  • Avira scanned at “fast” speed; avast! scanned at “fast” speed; AVG scanned at “average” speed; and Microsoft Security Essentials scanned at “slow” speed.
• The tests were conducted 1-5 months ago. In other words, Avira, avast!, AVG, and MSE (Microsoft Security Essentials) may have improved (or degraded) their performance since these tests were conducted. These are the versions of each program used for both of the above tests:

• The tests were conducted using the free version of Avira (“Avira AntiVir Personal” is another name for Avira Free); free and paid version of AVG, respectively for each test; and free version of avast!. Microsoft Security Essentials, of course, is free by definition.

Because of the above mentioned points,

• The performance of each software today may be different than when the tests were conducted.
• The performance of the free edition AVG may perform slightly differ than what is shown above since paid version for AVG was used for one test.

However, keeping that in mind, for the purposes of a simple comparison these test results work just fine because they give general indications, which is what we are looking for.

That being said, the results are a clear indication of Avira’s detection superiority. Not only does Avira have the highest on-demand detection rates, but it also tops the chart for retrospective tests; all with fast scanning and few false positives. avast! comes in a close second with healthy on-demand and retrospective rates, fast scanning, and few false positives. MSE is fourth in on-demand detection but does very well in retrospective tests and comes out on top when it comes to false positives. (It should be noted MSE’s lower on-demand rates help it do better in terms of false positives: It detects less so there is less chance of it to have false positives.) AVG, in my opinion, is the most disappointing of the lot. It doesn’t do too badly in on-demand but does terrible for retrospective and has many false positives.

Based off just these test results, Avira and avast! are definitely my two top picks, with MSE a close third. However, the tests were conducted in a lab setting for benchmark purposes. In other words, they don’t exactly reflect “real life”. In real-life usage the protection between all four program will be similar because most user activity will fall within areas covered by all four. I may be a bit bold when I say this but the differences between all four software will typically only be felt when conducting benchmarks or tests.

Malware Removal Effectiveness

(Click on the chart to view it in full size.)

Being able to detect malware has value in of itself; simply knowing you are infected is worthwhile. However, an anti-virus/anti-malware program that cannot remove malware is probably one you don’t want to have. Hence in the 3rd edition of dotTech’s guide on Best Free Windows Anti-Virus/Anti-Malware we look at the results of a malware removal effectiveness test.

Before we discuss the results it must be noted this malware removal effectiveness test had limited scope — it only used ten samples. It is hard, and frankly not fair or logical, to draw authoritative conclusions based on a test that only used ten samples. However, for the purposes of a non-authoritative indicator, this test will do just fine… as long as you keep in mind the limited scope.

That said, Avira once again tops the charts. MSE comes in a close second with AVG and avast! lagging as distant third and fourth, respectively. As I said, this test used only ten samples so we can’t say avast! or AVG are incompetent at removing malware while Avira or MSE are the best. The results very well could have been different if different ten malware samples were picked. (That is why having a large, randomized sample size is important in any test.) However, I believe it is fair to say with its combined stellar performance on-demand and retrospective detection rates and malware removal effectiveness, Avira more than makes up in performance what it lacks in features.

Computer Impact

(Click on the chart to view it in full size.)

(Click on the chart to view it in full size.)

(Click on the chart to view it in full size.)

NOTE: Avira Free 2012, avast! Free v6, AVG AntiVirus 2012, and Microsoft Security Essentials v2.1 were used for the above tests.

Generally speaking, the computer impact of all four software is about the same. True, avast! does come out on top but only by a small margin; and this small margin will only be noticed when benchmarking — not in real-life usage. Really the only test worth noting is opening Word and opening PDF. In this test avast! out shines the other three on the first run (subsequent run they all perform the same). All other aspects of the Computer Impact test end up with results that are too close to draw lines between.

(For those that don’t know, PC Mark is a professional, industry-recognized benchmarking tool. The higher PC Mark score, the better. However, when it comes to PC Mark, few points here and there have no significant meaning. If PC Mark scores were drastically different, such as 50 or more, then it would be worth looking at.)

Note: All tests referenced in all Performance Comparison sub-sections of this article were not conducted by dotTech. They (the tests) were conducted by AV-Comparatives.org, an authority on security software testing. I attained permission to re-publish AV-Comparatives’ results on dotTech when I originally wrote this article.

Final Verdict

While there are some noteworthy aspects – such as Microsoft Security Essential’s low false positive count or avast!’s lowest computer impact or Avira’s best detection and removal performance – there is no one “winner” between Microsoft Security Essentials, Avira Free, avast! Free, and AVG Free. To try to determine which one is the “best” is like trying to split hairs; it is hard to do and it hurts. In real-life situations, all four programs will provide users with excellent protection.

However, with that being said, if I were to rank these four I would rank Avira and avast! as my top two picks; Avira for its detection and malware removal and avast! for its features and lowest computer impact. Microsoft Security Essentials and AVG come after Avira and avast!, with each providing one or two unique features that have potential to win over users.

Now, what program you should use comes down to your specific needs and desires. Want the most features? avast! Free is the way to go. Are you looking for the best detection rates and don’t care about anything else? Avira Free is for you. Want a simple anti-malware program that provides great protection without nagging ads? Microsoft Security Essentials beckons you. Worried about network security? Microsoft Security Essentials’ “Network Inspection System” may serve you well. Are you a social network addict? Go with AVG Free for it has “Social Network Protection”. Hate false positives? Avoid AVG and consider Microsoft Security Essentials. Dislike slow scan times? Don’t get Microsoft Security Essentials. Surf the web a lot, besides your frequent websites? avast! Free’s “Web Shield” provides better specialized protection in that area than the other three programs. Download lots of software? avast! Free’s “Auto Sandbox” may be your next best friend.

I have provided you with the facts; now the choice of Microsoft Security Essentials, Avira Free, avast! Free, or AVG free is in your hands. Whichever one you pick, rest assured all four will serve you well.

Download Links

Avira Free AntiVirus

Supported OS: Windows 2000+

Avira AntiVir Personal homepage [download link]

avast! Free Antivirus

Supported OS: Windows XP+

avast! Free Antivirus homepage [download link]

AVG Anti-Virus Free Edition

Supported OS: Windows 2000+

AVG Anti-Virus Free Edition homepage [download link]

Microsoft Security Essentials

Supported OS: Windows XP and higher

Microsoft Security Essentials homepage

Originally written on February 14, 2010. 2nd edition posted on December 3, 2010. 3rd edition posted on December 18, 2011.