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Do Antivirus Suites Impact Your PC's Performance?

Do Antivirus Suites Impact Your PC's Performance?
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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.

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  • 1 Hide
    will_chellam , 11 October 2011 16:47
    I call error on your internet load times - I think your connection may be skewing things more than you think....

    I have a much slower PC than your test setup (E6600, 4GB ram, spinpoint HDDs) running MSE and norton. My connection is a CAT5e to 40mbps via a router....

    I have yet to see *ANY* webpage take more than 1-2secs to load....
  • 0 Hide
    damian86 , 11 October 2011 17:04
    Yeah well if we are talking about quad-core pc's then performance will be a secondary concern, but what about if we have an old pc single core,1.6 mhz,512 mb ram? I used to have Kaspersky i.s. and it used to kill it everytime it would update or do a rootkit scan,it would be there for ages..I just tried with nod32 and it seemed a bit better,now I am trying Avast and it is OK. What I mean is it is a concern for me,it is stupid to compare it to quad cores or actual pc's.
  • 0 Hide
    das_stig , 12 October 2011 02:44
    Don't know how your getting these figures for Vipre, but I use it across a range of machines from old P4's to AMD x6's and don't see any slow downs or excess scan times even in indepth mode.
  • 0 Hide
    Anonymous , 12 October 2011 04:49
    According to the Steam Harware Survey for September 2011, 49% of computers are still dual core and 40% are quad core. It would be intersting to see the same tests on a dual core machine....
  • -1 Hide
    dotxzer0 , 13 October 2011 12:40
    WHERE IS ESET!?!?!?!?!?!?
  • -1 Hide
    dotxzer0 , 13 October 2011 12:41
    HOW DOES GFI QUALIFY OVER AVAST OR ESET???
  • 0 Hide
    Anonymous , 14 October 2011 05:47
    The people than need good AV are people like my mum that knows nothing about computers and will happily click on a box that pops up if it told her to do so. Her PC of choice, an 8 year old pentium 4. It would have been really useful to see which is best on the old single cores.
  • 0 Hide
    Silmarunya , 16 October 2011 00:49
    brobblesThe people than need good AV are people like my mum that knows nothing about computers and will happily click on a box that pops up if it told her to do so. Her PC of choice, an 8 year old pentium 4. It would have been really useful to see which is best on the old single cores.


    Everyone needs a good AV. Who expects a downloaded chemical molecule model coming from a reputable science site to come packed with a virus? It happened to me and I'm pretty cautious.

    As for lightweight AV's: pretty much all AV's are lightweight enough these days even for old single cores.