Extreme CPU usage by Defender exe

[Guest]

Is anyone else having an issue with CPU utilization using Defender? I
noticed after installing a few weeks ago that my laptop is a dog now. Took
me a while to figure out that msmpeng.exe was the culprit. CPU usage changes
by huge percentages from 2 to sometimes 60% or more and consistently hovers
in the 30-45% range. Then, other times, it appears asleep at 0%. Is this
"normal"?

 

[Bill Sanderson MVP]

There may be several things happening here:

1) What kind of scheduled scan is set--full, or quick? I'd recommend
switching to quickscan for a daily scheduled scan.

When a scheduled scan is missed, it may happen some period of time after
startup. A full scan is quite resource intensive, and has no UI, unless you
open the Defender UI to see it. You can check the UI to see when the last
scan was and what kind of scan it was.

2) Sometimes high CPU usage appears to be associated with an A/V product
doing real-time scanning during a Defender scan--what Antivirus is in use?

3) I've believed that some reports like this when the issue comes at
startup, may relate to definition update problems. I think these are behind
us, but are your definitions apparently up to date?

 

[Dave M]

Are you running a scheduled recommended quick scan or instead a full scan
while this is happening? Is your processor capable of Hyperthreading and
is it enabled in your Bios if it is? Are you concurrently running any
other Anti-Spyware real time protection like Spybot S&D teatimer?

Mine never goes over 50% during a quick scan, and usually is around 30% for
the 2 minutes it takes to run, the rest of the time WD is pretty idle. So
it's important to post if this happens all the time which would make me
suspect a conflict, or only during scans scheduled or manually initiated.
You could also turn off real time protection to test the effect or check
your scan settings, to see if your running a full or quick scheduled scan.

 

[Guest]

I will try to answer both responses. Full scan, set to 2am and it's funny
that you should mention the delay. A lot of times, my laptop gets turned off
at night for one reason or another and would not have executed the scan. The
last scan was today at 10:49am which is, of course, when I had the issue.
Definition v1.14.1468.9. I am using Norton 2005 and it also runs full scan
in the early AM and is running real time as well. I didn't notice it burning
any cycles at the same time but I was fairly focused on Defender at the time.
I do not know if I have hyperthreading (I suspect not).

I suspect the delayed execution is the issue and since it seems to be
executing at somewhat of a random time, it may seem to me that it happens
"all the time" because of this.

I will switch to Quick Scan, try leaving my PC on/off, watch the last
execution time and keep an eye on it and see if there are any factors that
would lead me to believe that it isn't merely a timing issue. Thanks for
your quick responses!

Keanan

 

[Bill Sanderson MVP]

I think the fullscan, running (20 minutes?) after startup because of being
missed--is the most likely explanation. Norton is not a vendor I associate
with the high CPU usage during scanning.



--

 

[Guest]

Thanks. See reponse to Bill.

Are you running a scheduled recommended quick scan or instead a full scan
while this is happening? Is your processor capable of Hyperthreading and
is it enabled in your Bios if it is? Are you concurrently running any
other Anti-Spyware real time protection like Spybot S&D teatimer?

Mine never goes over 50% during a quick scan, and usually is around 30% for
the 2 minutes it takes to run, the rest of the time WD is pretty idle. So
it's important to post if this happens all the time which would make me
suspect a conflict, or only during scans scheduled or manually initiated.
You could also turn off real time protection to test the effect or check
your scan settings, to see if your running a full or quick scheduled scan.

 

[Rick Merrill]

Is anyone else having an issue with CPU utilization using Defender? I
noticed after installing a few weeks ago that my laptop is a dog now. Took
me a while to figure out that msmpeng.exe was the culprit. CPU usage changes
by huge percentages from 2 to sometimes 60% or more and consistently hovers
in the 30-45% range. Then, other times, it appears asleep at 0%. Is this
"normal"?

What about MSASCui.exe ???