Hey,
Turning on Web Shield and downloading files through one of these services results with higher cpu usage.
I have i9-9900k, and downloading with 600mbit/s speed (~65MB/s) on steam = 2.5 cores fully used on Avast (aswEngSrv.exe taking almost 2 cores, AvastSvc.exe taking rest)
Battle net:
disabled Web Shield = 0% cpu usage avast, 45-50MB/s download speed
enabled Web Shield = 2 full cores usage avast, 25-30MB/s download speed.
Yes, i already changed WebShield.ini with
[General]
UseStreamFilter=0
and nothing changed in matter of cpu usage.
I would like to disable this “feature” consuming whole CPU, without blocking REAL web traffic scanning.
Cheers
The only way I know to differentiate between Steam downloads and “real” web traffic is to exclude the Steam download URLs. I’m sure there was a list of them somewhere but I’m struggling to find it now, perhaps you will have better luck.
I don’t think excluding the Steam exe will work but you could give it a try using the instructions here:
Just to add, Steam recently changed the way it downloads your game updates in order to decrease the load on internet providers during the various lockdowns currently going on. If you’re not desperate to play those games immediately, you could just set a bandwidth limit in Steam and have it download them during less busy periods.
Edit: Found a list of Steam download servers here you could start with the more obvious ones like:
*.steampowered.com
*.steamstatic.com
*.steampowered.com.edgesuite.net
steampipe.akamaized.net
*.steamcontent.com
*.valve.net
Some of the others appear to be regional CDNs so may not apply to you, depending on where you live. Good luck, I can’t guarantee this will solve your issue but it’s worth a try.
i know this is 1 year late but the reason why it takes so much cpu is because Avast is scanning virus on your downloads and making sure no virus goes through your pc while you’re downloading.
It’s not that i care about steam/blizzard downloads. I am saying that Avast is consuming 2.5 cores on only 60MB/s stream and it is a big bottleneck here, i have top notch cpu, that have ~22000 points on cpubenchmark.
What can people with 4cores and 1gbit say? Get throttled internet by Avast while downloading? What is the point in here?
All i want is to have websites scanned that i open in web browser, not every single download on my pc… Separate it into different shields please. That is not the same. Yes, i know, it is downloading using HTTP/HTTPS, but NOT in browser.
there was an option to turn this off back in old UI, and it worked. Now i need to turn off whole avast to make it not thrash my cpu 
anyway, ty for reply
I’m just a dude on the internet, I didn’t make the thing. I dunno where you think this is, but it’s an unofficial Reddit community and nobody from Avast is likely to ever read what you are saying here.
If you just wanted to have a cry you could have saved me the trouble of finding you a potentially working solution you weren’t interested in by making that clear from the outset. Also I’d point out that you specifically mention Steam and battle.net in your title so you can understand my apparent confusion.
Sorry, didn’t mean to insult you in any way, i am just bit pissed they make one of the best shields (didn’t have virus for over a decade), yet, they do weird mistakes lately by putting such crap in their software…
No worries 
There is the option buried within Avast to limit Web Shield to “Scan traffic from well-known browser processes only” but I don’t know if this will work for you in this instance. (Settings → Troubleshooting → Scroll to bottom, “Open old settings” then in the new window that appears, Components → Customise next to the Web Shield, then tick “Scan traffic from well-known browser processes only”)
Careful though, this will reduce your security and I’d still recommend instead to exclude particular trusted URLs like I described initially.
This didn’t make even a little change, but “Use intelligent stream scanning” - i was looking for it, i remember it changed cpu usage back in the days.
I have dropped from like 3-3.5 full cores, to only 0.5-1. Thank you!
anyway, ty for reply