Although I don’t know the answer to “what can cause 100% CPU usage when scanning”, I have a different perspective on such issues.
First, if there are other processes using much CPU cycles simultaneously, then running a scan is yet another process in need, so there is always such possibility of 100% CPU usage.
But anyway, if there is any percentage of CPU not being used (free), and I run “something” (a scan in this case) that has the potential to take advantage of “free” CPU cycles, I indeed would want this process to use all the CPU it can.
If I already have 100% CPU usage, then it is a matter of priority. Which process, of all those active, I want it would take more advantage of CPU resources.
For those using more than 1 core, it would be very good news if all cores could be used simultaneously every time. Unfortunately, this is not always the case, and some processes take more time than they could if they were able to really take advantage of all the available resources.
So, although there is a possibility that indeed your CPU usage is “too high” beyond the “normal expected” usage, it is also possible that the processes running are actually taking advantage of all the resources they can, hence working as fast as they can.
This is only my point of view, and, as I said, there is still a possibility of this high CPU usage being a real issue to take care of.
Whilst that may well be true in limited cases as there really is no way to test for every system permutation, hardware/software(?).
The CPU would jump on initiating a manual scan A) depends on the scan, B) the areas selected to be scanned, C) the settings of the scan and D) what else you are running in the background.
To start with there is a degree of initialising, were it is being determined exactly what is to be scanned and this is likely to be CPU intensive I have never seen my CPU get up to 100%. But it should soon drop back so it doesn’t impede the system, unless you have changed the scan priority.
Well that isn’t entirely correct as I’m not really watching this like a hawk, I would only check it if the initiation of the scan impacted on my use of the system, which I haven’t seen.
Make sure you fully remove AVG before reinstalling avast and it would also probably be best to run the avast uninstall utility (for the old installation) before reinstalling 6.0.203.
Download the latest version of avast, 6.0.1203 http://files.avast.com/iavs5x/setup_av_free.exe and save it to your HDD, somewhere you can find it again (if you didn’t save your last download). Use that when you reinstall.
Download the avast! Uninstall Utility, aswClear.exe find it here and save it to your HDD (it has uninstall tools for both 5.x and 6.0.x).
Ensure that all remnants of AVG are gone - AVG8.x (or higher) Remover, download tool from here, http://www.avg.com/us-en/utilities there is a 32bit and 64 bit windows version, ensure you use the correct one.
Once you have all the tools downloaded and saved:
Uninstall AVG using add remove programs, reboot and run their AVG Remover tool, reboot.- 2. run the avast! Uninstall Utility from safe mode, first for 5.x if previously installed and then for 6.0, once complete reboot into normal mode.- 3. install the latest avast! version, reboot.
Open the Task Manager, you can check the CPU and memory usage and network as well. For 100% CPU usage, may be one or more process(es) taking too much CPU cycles such that cause your computer looks freezed, you can goto second tab (process running), you can view which process(es) taking high CPU cycle. In normal case, only “System Idle Process” take the most CPU cycles, so that the kernel can handle IO devices normally.
Yes, me too.
I know I’ve tried a clean install before with no results. The only difference being, I didn’t do an avast 5 remove with the removal program.
This time, I’ll be sure to have avast on default settings.
Also, I should mention, this problem only occurs with my desktop. The laptop has no problems.
Also, the last time I did a clean install, during setup, when avast does a ‘quick scan’, it was fine. The problem occurs after avast is finished installing and I run a scan, either quick or regular, from the GUI.
This is really strange and driving me crazy.
I remember reading a post about a similar problem a user was having and there was talk about file unpacking or something? It was some process popping in and out, similar to what I experienced. The user did not want to go back to the default settings. That’s really the only thing I can think of out of the ordinary for me.
In addition, in Avast main GUI → Settings → “Troubleshooting”, you may try for example “Load avast! services only after loading other system services” or some other option. Just a thought.
Thanks for the ideas. Previous programs are the obvious suspects, but I’m pretty sure every thing is gone, unless there is a ‘tool’ to find any remnants.
Have you done any runs with any antispyware programs?
100 cpu usage can be caused by spyware running in the background or lack of ram memory. Is hard drive running in DMA MODE?
Your system is fine with the amount of ram is installed
If I understood correctly, you used to have AVG? Look at the link I posted for the specific uninstall tools for AVG (made/produced/published by AVG and recently updated). Run it under Windows Safe Mode.
I’ve done as everyone suggested, but no go. Short of reformatting the HD, which I’m not willing to do just to make avast work, I’m moving on.
It’s just odd that other AVs work.