Avast scan time faster than usual?

[system]

I noticed this started occurring the same time the recent exception code errors happened (http://forum.avast.com/index.php?topic=58762.0)

My scans are now running twice as fast as normal. For example, on 4/18, a full scan took 1 hour, 2 minutes, but from 4/20 onwards, it takes just 28 minutes. I was just wondering if this is a new feature in Avast that makes it run much faster than before, or if there’s a problem/error.

I’m using Avast free 5.0.507 and database 100422-1

[Lisandro]

avast 5 should run faster than avast 4.
If you’re using persistent cache, subsequent scannings from version 5 could be faster.
The scanning speed also depends on what you’re doing in your computer (number of files and archives, etc.).

[system]

This i know happened to me also,Please see this topic i started a few days ago with some helpful advice…
http://forum.avast.com/index.php?topic=58853.0

[system]

I never had Avast 4, only 5. I’m not using the persistent cache either. Basically, nothing was changed between the dates of the two scans, other than the database updates.

[igor0]

Yes, the speedup was caused by some improvements in the scanning engine (contained in the “virus database”). It manifests only for specific scans, such as the default “Full system scan” task.
There’s room for additional improvements… that will most likely happen in the next few virus database updates.

[Asyn]

@igor post:5

There’s room for additional improvements… that will most likely happen in the next few virus database updates.

Wow…!! ;D 8)

[system]

Mine seems to have settled at around 7 minutes (down from 40+). ;D I used to run a mix of quick & full scans throughout the week but just run full scans now. ;D ;D

Kidd

[system]

That’s amazing, my scans generally take ~1 hour no matter which AV I use, but I certainly don’t mind the new faster scan times.

Are the scans still as effective as they were before?

[system]

My flash drive 1.7 GB data, took very few seconds :o with 5.0.507 !?
I repeat
Are the scans still as effective as they were before?

[Vlk]

Yes, the changes have no effect on the efficiency of the scans… I plan to have a blog post soon when I’ll explain what changes we have implemented, and why they usually have such a dramatic performance gain.

According to our testing, on a typical system the speed-up of the Full System Scan is 2-6x.

[Rednose]

Nice

Full System Scan went from 1.06 h. to 25 min. here :o

Greetz, Red.

[system]

@Vlk post:10

According to our testing, on a typical system the speed-up of the Full System Scan is 2-6x.

Well done… 8)

[Vlk]

Here is the promised blog post: http://blog.avast.com/2010/04/25/how-to-make-the-full-system-scan-6x-faster-in-10-days/

Thanks
Vlk

[Asyn]

@Vlk post:13

Here is the promised blog post: http://blog.avast.com/2010/04/25/how-to-make-the-full-system-scan-6x-faster-in-10-days/
Thanks
Vlk

Thanks a lot for the link and the speed up, of course…! Again very good work…!!
asyn

[system]

LOL I was gonna post a new thread… not needed anymore. After a new install yesterday, I was reluctant to run a full scan (to populate the persistence cache on all drives) and it generally is quite resource demanding and you never know how long it lasts (I’ve had times between 15 minutes up to almost two hours in a first scan after first full scans on misc Avast 5 builds). Anyway earlier today I run an explorer scan (set to write to cache as well as to read from it) on Windows folders >>> winsxs, system32 and others, it was lightning fast : So I thought I was gonna post about it, wondering why it was that fast, while scanning the same folders, the full scan preset usually takes ages to scan, also considering the fact that the explorer scan scans “deeper” (whole file enabled) than pre-set scan…gonna test the full scan again now and report back…won’t be relevant unless I delete all persistence cache data as many folders have already been scanned otherwise.

ps: thanks for your blog post Vlk, that’s really interesting

edit: just wanted to add that subsequent scans to a first full scan, on my system, have always been dramatically reduced (duration)…I never observed that times were the same…not the same gain as with the quick scan, but still, reduction was from 1 hour (first scan) to 18 minutes with new scans.

[system]

what I can say so far, is that the writing to persistence cache is definitely much faster than before…

[system]

I have just run two full scans, and have not seen any inprovement…

initial scan:
Time: 30:17
Data: 94.44 GB

2nd Scan:
Time:28:10
Data: 94.47

Running a third now, but it looks to be that it is going to be similar…

Although, I am not sure if I have done any full scans prior to this…

-Scott-

EDIT: That said, I can see where the cache is having effect…about 30 - 70 is very quick as it scans the windows stuff…the rest though is no different…

[system]

yes definitely scans following a first full scans, ie when the persistence cache has been written already, are not faster than before, but again, a first full scan, when cache gets written, is much faster that it use to be.

[system]

so about 30 is the shortest it will be for me then?

I usually only do quick scans anyway so not that bothered…

[igor0]

@Logos post:15

edit: just wanted to add that subsequent scans to a first full scan, on my system, have always been dramatically reduced (duration)…I never observed that times were the same…not the same gain as with the quick scan, but still, reduction was from 1 hour (first scan) to 18 minutes with new scans.

The “Full system scan” has kinda special settings - the option “Speed up scanning by using the persistent cache” in unchecked, while “Store data about scanned files in the persistent cache” is checked. That’s where the second speedup takes place.