How to fix Avast Antivirus High CPU Usage

Discussion in 'Security and Anti-Virus Software' started by Ultra Male, Mar 2, 2016.

  1. Ultra Male

    Ultra Male Super Tweaker

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    So a while back, I noticed that my CPU performance was decreased. I tested using wPRIME running a 32M benchmark. Without an Antivirus installed, I would get a score of 4.9 seconds, with Avast Antivirus Pro installed, I would get 7.5 seconds (the lower the score the better).

    I then posted this thread on the avast support forums:

    Avast Antivirus Pro affecting CPU Performance

    No help was offered and I was just told that any Antivirus would cause a small hit on the CPU performance.

    I then installed NOD32 and Kaspersky Antivirus (separately off-course) and benchmarked again but I would get 5 seconds in wPRIME so that was all good and the issue seemed to only be there when Avast Antivirus was installed.

    This surprised me because according to the latest AV-Comparatives Performance tests, it shows that Avast Antivirus is one of the lightest solutions out there.

    I then submitted a support ticker to Avast which as usual, took almost 2 weeks to be answered.

    They suggested to change a few things which I did and now my CPU performance is back to normal, I am getting 5.3 seconds in wPRIME so a 0.3 seconds performance hit is fine.

    Here are the suggestions from avast! Support to remedy this problem whilst not really affecting your security:

    @Ethrem
     
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  2. Tinderbox (UK)

    Tinderbox (UK) Sir Pumpkin Longshanks

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    I have been using Avast for years because of the low cpu usage, I get free Kaspersky though my bank but i has high cpu usage, So no problems with Avast.

    I have an gadget that monitors my system top five highest cpu hogs and avast is rarly on the list.

    John.
     
  3. Ultra Male

    Ultra Male Super Tweaker

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  4. Tinderbox (UK)

    Tinderbox (UK) Sir Pumpkin Longshanks

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    Kaspersky use to use 90-100% during a scan, Avast is super light weight compared to that.

    I just checked Taskmanger and it has avast using 0% cpu, as it`s not scanning at the moment, when it does scan it might go to 25% but for 15min or so and then stops, I suppose how long the scan takes depends on how fast you cpu/hdd/ssd is and how many files it has to search though.

    John.

    [​IMG]
     
  5. Ultra Male

    Ultra Male Super Tweaker

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    The right way to test it is, run wPRIME 32M benchmark with all threads which should be 8 if you have a 4 core CPU(go to settings in wPRIME) with avast! installed, then uninstall Avast and run the benchmark again, not immediately after a restart but after a few mins of being idle then see

    PS: Disabling all Avast Shields doesn't count, it has to be uninstalled to see the difference before/after, if you have time to do this that is, maybe take an image before uninstalling it
     
    Last edited: Mar 2, 2016
  6. downloads

    downloads Super Moderator Super Moderator

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    As always, your mileage may vary. I've seen people say they dumped Avast because it was causing high CPU usage on their laptops and at the same time having tested multiple solutions, I chose Avast to run on my Atom-powered convertible, exactly because it has low CPU and very low RAM footprint while providing very good security.

    I'll check those recommendations though - I think I might want to consider disabling "intelligent stream scanning" as Avast tends to eat up quite a lot of CPU when I'm downloading multiple files @ 100mbps. I'm guessing that's the reason - it attempts to scan multiple files at the same time coming at it at a steady 12MB/s
     
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  7. Ultra Male

    Ultra Male Super Tweaker

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    Good idea, please try the above recommendations and tell us if you see a difference. As support said, this will not lower your security because once the file is downloaded, if it was malicious, the active file shield will block it anyway so no harm done.

    I personally dislike programs which do HTTP scanning, like I have a NOD32 license for 10 users valid until 2020 which is collecting dust as it slows down everything for me, internet browsing, downloads, etc. wish I could sell it
     
  8. Tinderbox (UK)

    Tinderbox (UK) Sir Pumpkin Longshanks

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    Yeah, I disable Avast bloatware app that i dont want to pay for, it`s sill not to.

    Yeah, I have use Avast on my Atom cpu table as well, no high cpu usage on it`s tiny little 900 passmark cpu score, my i3 i am using now gets around 2500 points and that is quite low to most modern cpu`s

    Those that use torrent downloading apps can expect to have high anti-virus cpu usage as all files need to be scanned and zip files are extracted and files scanned individually in the background this can use a lot of cpu power.

    John.

    EDIT: Hi i found this 2015 AV comparison test, and they also rank them by cpu usage.

    http://features.en.softonic.com/windows-antivirus-comparison-2015

    John.
     
    Last edited by a moderator: Mar 2, 2016
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  9. Ultra Male

    Ultra Male Super Tweaker

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    @downloads

    On the avast forums, one moderator said the following:

    Can you please delete this thread as I don't want to cause any security risk to anyone.

    Thank you
     
  10. downloads

    downloads Super Moderator Super Moderator

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    Let's leave it - it's valuable to know both what to and what not to do. Someone may come across it and find it valuable - granted not the way first intended.
    Also Some of these tips from support remain valid - only intelligent scanning and script scanning should not be switched off it said moderator is right.
     
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