Most of us are now fairly confident that our antivirus scanners are doing their main job of protecting our systems from malicious pests. But what are those scanners doing to system performance behind the scenes? Are some scanners better than others?
Let’s start with the good news: antivirus products all work. If what you care about is protecting your system from viruses and similar digital pathogens, just about every major vendor in the AV space does a respectable job. But don’t take my word for it. Check out AV-Comparatives, which currently evaluates 20 of today’s most recognized names in the antivirus world.
The above chart shows AV-C’s results for August 2011. Now compare against the same tests done in August 2010.
While it’s interesting that the three top performers on these charts are consistent, the point is that most players can change considerably from year to year, and even month to month. Does anyone really think that Microsoft went from 98% accuracy in 2010 to 92.5% and stayed there? As if the company suddenly forgot how to write virus definitions? No. Quite literally, sometimes AV companies have bad days. In the 2011 AV-C tests, Sophos and Webroot (which uses Sophos technology) were the only vendors to be dropped from the testing because the cloud-based portion of Sophos’ definition set was down.
As multiple vendors agreed in interviews with us, when it comes to detection and isolation of modern viruses, worms, bots, and so on, just about everyone does at least an adequate job.
“Most of us are close,” says Dodi Glenn, product manager at Vipre Antivirus. “The thing is, you could say that you detected some sample set, and your AV is better than mine. But if you fast forward, I could say that you missed X, Y, and Z. There’s a notion of when you gathered the data. And is it a zero-day? Has it never been seen before? Is it a proactive or reactive type of detection? It all depends on the sample set you’re using. In theory, your efficacy rate is going to change any time you update.”
Accuracy may no longer a primary criterion for product selection, although it should still be considered as a secondary item after pricing and full AV suite functionality. There is another side to consider with AV products, though, and long-time Tom's Hardware readers know it well. What impact is the software having on your system? Loads of features and stunning detection accuracy may be impressive, but if the background AV product is sucking minutes or hours of your productivity and performance away from foreground tasks, you have a problem. In general, for reasons we’ll discuss soon, we are less concerned about the impact of scheduled scans than we are about the low-level monitoring that today’s AV products perform constantly. Will they slow your gaming? Will they balloon your Web page load times?
We don’t need an exhaustive answer from examining two dozen names. We figured that half of a dozen would do for establishing whether or not AV products in general are dragging on your system and if there is a significant variance in this drag between products.
- Antivirus Need...and Greed
- Contenders: AVG And GFI
- Contenders: Kaspersky And McAfee
- Contenders: Microsoft And Symantec
- How We Tested: Configuration
- How We Tested: Benchmarking
- Application Installation
- Boot Time
- Standby Time
- PCMark 7 Results
- PCMark 7 Results, Continued
- Web Page Load Time
- Scanning Time
- Do Antivirus Suites Have A Big Impact On Performance?


i think something is wrong with your numbers.
Also, the timing of this article was excellent. I had just been doing some research about what anti-virus software I should switch to, mainly based on performance, but I guess I just got all the information I needed.
I stopped using AV products on my personal systems back in 2003. Norton back then was god-awful on a Pentium 4 systems, seemingly crushing the life out of a system. Even with a first generation WD Raptor 36GB my P4 2.6 would choke not only with Norton, but also McAfee. I might not use AV software, but I do put it on my family members' systems when it doesn't kill performance. In that respect these modern solutions seem much better.
>>Apparently, this is somewhat like saying you can boil water at 230 degrees Fahrenheit instead of 260 degrees. As long as the water is at 212 degrees or higher, no one really cares.
i think something is wrong with your numbers.
I had kaspersky on my intel i7-920 system with a SSD app/boot drive, and kaspersky brought my system to it's knees compared to a clean system without any antivirus. It was like a computer from 7 years ago in it's response time. Try to install something? Took 10 seconds to start the pre-scan, then it would pre-scan and then install was slower. Run firefox from a fresh boot? Wait 3 seconds. 3 seconds? With a SSD?
I removed it and tried out norton internet security and everything is instant like my clean system. I don't even notice that I have it most of the time. I attribute that partially to my good system, but I attribute the other part to it not just adding arbitrary wait times onto everything I try to do. Use that processor! I have multiple more to spare!
I know people think dirty of Norton, but as long as it protects me while pretty much being invisible to my performance to the naked eye, I'll give the once slow kid in the class if he's a genius now. I don't know why, but it works.
Tom's something is wrong with your test bench.
If anyone is interested, I did ran my own tests for most of the latest security suites and have reached to the conclusion that Avast 6 is the fastest around. A scan on 10 GB of data on an SSD took ~2 minutes , compared to 8 minutes it that took Kaspersky to finish the same job.
I agree that Avira free should have also been included to balance the field a little bit.