Avast Shields Scans What MalwareBytes Is Scanning, Using extra resources

[rhyme-time]

Im not sure if this is an Avast problem or Malwarebytes or if its even a problem at all..

I notice when Im doing a scan with Malwarebytes Free, some of the files its scanning, Avast file system real time shields also scans them. Avast uses around 20 CPU and it slows done my computer a little bit. Mainly the files are in the C:\Windows\Installer folders and some of the Microsoft .NET Framework files. Also I notice some of the files are Javascript ones (.js).
I do not have the file system shield set to Scan All Files.
Is this normal?

Thankyou.

-
Windows Vista 32-bit, Avast Free 8, Malwarebytes free.

[Pondus]

the realtime shield scan all files that move in the background when the comp is on..
so yes when mbam is fiddling around with those files the realtime shield is watching

[DavidR]

That is a consequence of having other security software installed, depending on the file type and action. It also depends on how MBAM is opening the file for scanning, if it were only opening it for read permission then avast is unlikely to duplicate the scan. If however it is opening it with higher privileges, write for example then avast would scan it first.

I don't think it is scanning every file or even the majority that MBAM is scanning, you can check the File System Shield stats (files scanned) before starting the MBAM scan and compare when finished. You can check against the number of files scanned by MBAM and it will give an idea of what avast may be scanning.

A long time ago I used to pause the avast file system shield before starting another third party security scan. That avoids the possibility of conflict between both scanners in the event of them both getting involved in a fight over a detection that they both recognise. It also avoids the duplication that you find and the consequent increase in scan duration.

Now I don't bother with that as my system is up to the additional load and the possibility of conflict low as I don't expect to see any detections on my system.

[rhyme-time]

I didn't say it was scanning all files, just some. Mostly when it gets to the windows\installer folder. (And I think maybe some of the temp stuff)

I did a test to see how much files avast scanned.

Before I did the Malwarebytes Quick Scan, Avast File System Shield had 7053 scanned files.
After the Malwarebytes Quick Scan, Avast File System Shield has 7258.
Malwarebytes scanned 200210 files.

So avast scanned 205 files.

During this time I did nothing else but scan, did not touch it.

I guess its not important, but Avast uses 30-40 CPU.... I guess I should disable the File System Shield while scanning, but I don't feel so comfortable with that......

[DavidR]

I would say 205 files scanned by avast out of 200210 scanned by MBAM is very small almost of no significance 0.102%  and not all of those files avast scanned will be files directly scanned by mbam. Avast's file system shield will be continuing to scan other file activity on the system.

However, that said, these aren't files scanned by mbam, but what they are calling objects, this includes scanning registry entries, etc. unfortunately it doesn't give a breakdown of those categories, so the actual 'files' scanned would be less, making the percentage of files scanned by avast greater.

So I really don't see this as a problem, certainly not one I would consider stopping the file system shield whilst an mbam scan is running.

What you don't say in your topic is what your CPU and RAM are as these are more crucial when you are talking about CPU usage. If you don't have much RAM

[rhyme-time]

Uh I hope this is the information you need:

Intel(R) Core(TM)2 Quad CPU   Q6700  @ 2.66GHz  2.67 GHz
4.00 GB of RAM

I know that its not alot of files that avast scans but I can hear my computer go quite loud and Avast uses 30-40 CPU. It only lasts for a minute or less of the MBAM scan. Probably 40 seconds.

I just wanted to know if it would be a problem for my computer or not. Thanks for answering so far.

[DavidR]

Well that should be more than enough, it is certainly much more than mine, but I don't see any issue with CUP usage during mbam scans, but I run them scheduled at a time when my system is on but not busy. So I wouldn't worry about CPU at 30-40%.

I just ran a test, MBAM Quick scan 215653 objects scanned, avast FSS files scanned before 2946 FSS files scanned after mbam scan 3714. Now my avast scanned more files during that period, but I monitored my task manager and avastSvc.exe (the main scanning engine/process) was generally at 5% or under and saw one peak at 11%. Overall my total system % was 30-40 (nothing like that for avast) with mbam.exe around 15% with peaks above that (one short one of 45%, just as it was closing down the scan), the mbamservice.exe was usually running at about 5% less than mbam.exe.

So no real issue here and my FSS settings are possibly higher heuristic sensitivity than yours High heuristic sensitivity and Use code emulation, other than these it is pretty much default settings, Advanced all options are checked.

This may account for the greater number of files scanned during the time of the mbam scan. What it doesn't account for is my CPU activity much less, whilst having scanned more.

[rhyme-time]

Actually, my File System Shield IS set to the highest heuristic sensitivity AND use code emulation.

But if it means theres nothing wrong with my computer, then I guess its okay. It wasn't bothering me, I just wanted to make sure it didn't mean there was something wrong with my computer.

[DavidR]

No it is expected that you will get some duplication whilst scanning, I'm just surprised that yours is much greater than mine, given your system specs and mine in my signature.

[rhyme-time]

Yes, Um I think this computer was suppose to be good for playing games or something, or atleast at the time.
I really have no clue about Processors and RAM and anything like that.... I know them but dont know what they do and stuff...

I guess this topic is solved if it isn't a problem or means theres something wrong with my computer.
Do I (Or a mod) have to lock this topic or something...?

Thankyou!!

[DavidR]

We can't say if it is a problem, what you should be looking at (excuse the pun), not the task manager stuff, but how your system is running whilst this scan is on. If it doesn't feel sluggish, lacking in performance, etc. then it isn't a problem.

Whilst I generally have my scan set to run at a time when I'm unlikely to be using any resource heavy background programs, but I can carry on browsing and other light tasks without feeling any lack of system performance.

[rhyme-time]

Well, it does go a bit slow when avast starts scanning the files malwarebytes scanning but malwarebytes quick scans only takes for 2-4 min for me and when I do a full scan I usually leave it.

But, it sounds like my processor or RAM is good, maybe? But when something (Anything) is running at just 30 CPU, it seems to lag a little  bit... Could that indicate a problem with my computer? Or is that normal?

[DavidR]

It is really hard to say as we don't know what else is running on your system as that will contribute to the avast activity over and above what is as a result of the mbam scan running.

Whilst my system CPU spec isn't as fast as yours, plus less RAM, the main difference is my OS is XP Pro, which is somewhat lighter on resources than Vista.

[AU4U]

Ever consider setting some exclusions for MBAM  in avast,,,and avast! in MBAM?

[DavidR]

Exclusions for mbam in avast won't make any difference in on-demand scans, as all you are excluding the mbam executable file/s and not what it does. So it might not be scanned, but it is still likely to trigger avast to scan some of the files it opens for scanning.