Avast uses excessive CPU time

[arbee83]

I just installed avast! Home Edition on an older Dell laptop. After installation, the computer runs very slowly. Task Manager shows start.avast using anywhere from 25-35% CPU time. The laptop is nearly useless since total CPU usage is nearly 100%. If I disable avast!, CPU usage returns to normal. My desktop running avast! Home does not even show start.avast in Task Manager. Any ideas?

[Tarq57]

One of the most likely causes of this is the remnants of a previous av on the computer. What was the AV prior to Avast, and how was it removed?
(Some have special removal tools. Links will follow after your reply.)

[DavidR]

What are the system specs, Operating System, CPU, RAM, How much data on the hard disk being scanned.

There isn't a start.avast process, you possibly mean avast.setup which is the update process running. If you have broadband always on connection then when a connection is established avast will check for updates and this does use CPU and RAM resources.

However, depending on OS the auto update process restricts its CPU use (question above), so then we are into what other process are running one boot (AV as Tarq57 mentions). Many applications when installed insist on starting on boot where there is no need, media players are typical of this. Only essential applications should run on boot, OS system stuff, security applications, AV and firewall, etc. this reduces the load on boot a very busy time.

[arbee83]

You are correct: the process is avast.setup. With no apps running, this process used to take approx. 25% of CPU time. I just installed the latest version of avast! and avast.setup no longer appears in Task Manager. If I start Firefox, that goes down to almost zero, but Firefox (or IE7) takes close to 80% of CPU time. On my desktop, Firefox uses less than 5% CPU once it is running. Last week, I reloaded Windows XP Pro for this very reason: CPU time was running at or close to 100%. I had avast! running before that time with no problems. I'm guessing I have a hardware issue. The computer is an older Dell Inspiron 1150 with 512 MB ram and a Celeron processor (not speedy on a good day). This is not my primary computer, and its a good thing, since I have the liberty to play with it. In any event, avast! does not appear to be the issue. I appreciate your responses.

[DavidR]

No problem, glad I could help.

The avast.setup only appears in the Task Manager when it is actually updating avast when complete it is removed (so no resource use).

Welcome to the forums.

[Lisandro]

If avast.setup process does not disappear, it is due to update process hanging.
The better will be killing that process or boot the computer.