Author Topic: Avast killing internet speed  (Read 12066 times)

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Offline alanrf

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Re: Avast killing internet speed
« Reply #15 on: December 14, 2007, 11:38:28 AM »
I remain perplexed.

I do not want to sound like one who never questions the impact of avast (just ask the avast team) but there is still the unexplained and dramatic difference in speeds of FTP downloading files reported by the poster when avast is totally uninvolved.  If this system has such differences in subsequent FTP downloads of files where avast is not involved then what reliance can be placed on the timing of file downloads when avast is involved?

In my last tests I reported in this thread I performed the same download via a port scanned by avast and then on a port not scanned by avast.  So - to be clear - the avast Webshield was operative in the system on both tests but only scanning one of the file downloads.  The download on the session not scanned by avast was slightly slower than the session scanned by avast.

I have just repeated my test but this time I made it a little closer to the test reported by the poster.  I just downloaded a  157Mb file via http first with the avast Webshield active and then with the Webshield terminated.

Test 1 - Webshield active - download speed 825.55 KB/sec
Test 2 - Webshield terminated - download speed 823.51 KB/sec   

I must conclude that my tests are within the differences one must expect of network connections and again I will not assign to avast the slightly faster speed with the Webshield active. 

So what are the differences?

I am using Windows XP SP2 but I think that we have not yet been advised of the OS of the poster ... could this be a XP versus Vista difference?

The poster clearly has a basically faster connection than I do ... is it possible that avast can penalize very fast connections but not slower ones?

There is still the very nagging question I posed at the start of this particular post.  Can I ask the original poster to look at the possibility of providing some figures based on an average of sample downloads?
« Last Edit: December 14, 2007, 11:41:15 AM by alanrf »

Offline avastnoob

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Re: Avast killing internet speed
« Reply #16 on: December 14, 2007, 07:50:57 PM »
alanrf

This is a fresh install of Windows XP SP2 on a brand new formatted HDD. I am using the latest version of firefox as my browser and using Comodo (the last version prior to release of v3) as a firewall. ISP is VirginMedia 20Mb/s.

When I was downloading files to update the PC after the WinXP install I noticed that I was only getting around 14MB/s download speed wheras for the last few months I have had a rock solid 18/19 Mb/s on fast sites like AMD / Microsoft / Epson etc.

Aware that VirginMedia's tech support is
a) expensive and
b) bloody awful and they will always blame their customer's PC / Anti Virus / Firewall,
I started testing by turning the antivirus / firewall software off before I called them.

From doing this I narrowed the problem down to the webshield of Avast. It is totally consistent - turning on webshield reduces web download speeds by around 5 to 6 Mb/s

I have to admit that I have again tried the ftp download and it seems that maybe there was a blip in the result the other night as tonight I am getting

Webshield ON - 82.92Seconds 2377.69Kbytes/sec
Webshield OFF - 86.97Seconds 2267.05Kbytes/sec

However, trying the 117.7Mb M/s download fromthe M/s website again I am getting

Webshield ON - 61 sec
Webshield OFF - 48 sec

I have also tried a 39.5Mb file from Epson

Webshield ON - 21 sec
Webshield OFF - 16 sec

I should also mention that I have tried other PCs on the network
Work laptop with McAffee a/v
spare PC with AVG a/v
Wife's work laptop - can't remember what her firm uses as a/v
and all are downloading at 18/19 Mb/s
« Last Edit: December 15, 2007, 01:02:54 PM by avastnoob »

Offline alanrf

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Re: Avast killing internet speed
« Reply #17 on: December 16, 2007, 10:27:50 AM »
I do not believe I have access to the MS file you used for testing. If the Epson file is freely available can you post a link please?  I would like to test with same file that you have also used. 

I do understand the reports of the other systems - but - as a (very) old hand in the business you will, I hope, understand that a true test would require you to uninstall avast on your system and try McAfee and uninstall whatever on your wife's work computer and install avast.  Comparing these systems - while not unreasonable - is not a truly reliable diagnostic and I certainly understand the limits that you might be willing to go to.

I think that you can appreciate too that, were this a more general issue affecting other avast users, this forum would be lit up like the proverbial Christmas tree.   
 

Offline avastnoob

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Re: Avast killing internet speed
« Reply #18 on: December 16, 2007, 12:39:35 PM »
microsoft office 2003 SP3 -        http://www.microsoft.com/downloads/details.aspx?FamilyId=E25B7049-3E13-433B-B9D2-5E3C1132F206&displaylang=en 

I cannot remember what the epson download was - it was merely a largeish file I found on their website the other night which I chose to download merely for the purpose of testing download speeds.

Appreciate your help so far. I too am totally perplexed as to why this happening. As I have not got round to totally re-installing everything on my PC after the XP re-install I may try re formatting and re-installing over the Xmas break and see if that makes any difference.


Offline alanrf

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Re: Avast killing internet speed
« Reply #19 on: December 17, 2007, 12:22:50 AM »
Ok, I just did the test with the Microsoft file in your link.

I too am using the latest release of Firefox but I only use the native XP firewall.

For me:

Webshield on  02:12 (914.21 Kbytes/s)
Webshield off  02:20 (858.44 Kbytes/s)

The only consistency for me (and I ask you to believe I am not faking it) is that it is faster with Webshield on. 

However, that made me think.  The big difference with Webshield on and off is who is actually doing the reading from the Internet.  When the Webshield is off it is Firefox actually reading from the network; with the Webshield on it is ashWebSv.exe that is reading from the network. 

This leads me to a couple of questions:

1) Are you using any kind of accelerator (Google plugin) or any other "speed-up" extension in Firefox?
2) Could you please try to repeat your test with IE (assuming you do not have any accelerator plugins with it) and see if you get the same difference in downloads with Webshield on and off?   

Offline Lars-Erik

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Re: Avast killing internet speed
« Reply #20 on: December 17, 2007, 12:36:06 AM »
I am finding that the Webshield is reducing my internet speed by 5 to 6 Mb/s. If I turn the webshield off it goes back up to full speed (20Mb). Does anyone know why this is the case and if there are any settings I can alter

Can't say anything else then that I have noticed the same and had to disable the web-filter
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Offline avastnoob

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Re: Avast killing internet speed
« Reply #21 on: December 17, 2007, 07:19:19 PM »
Just done tests tonight with the m/s 117.7Mb file

Firefox webshield ON - 58 secs
Firefox webshield OFF - 45 secs

IE7 webshield ON - 68 secs
IE7 webshield OFF - 58 secs

I do not use any accelerators in either Firefox or IE

Still a big difference between having webshield on/off but also a big difference between IE and Firefox. I have noticed in the past that the initial "burst" speed on firefox seems a lot higher than on IE

Offline avastnoob

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Re: Avast killing internet speed
« Reply #22 on: December 23, 2007, 03:22:33 PM »
Well, I tried a complete Win XP re-install but still got the same thing -  a consistent 4 to 5 Mb drop in download speed with Webshield on. No idea what was causing it but have now re-installed Win XP yet again and reverted back to Norton where I get the full 20Mb download speed that I pay for.

It's a shame as Avast seemed good other than that

Offline Lisandro

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Re: Avast killing internet speed
« Reply #23 on: December 23, 2007, 03:28:22 PM »
Well, I tried a complete Win XP re-install but still got the same thing
I don't think 'overinstallation' will solve or help in this case... if something is wrong, it will be there after overinstallation. Maybe (although is a pain) we can only test with an installation from the scratch.

It's a shame as Avast seemed good other than that
Indeed, speed shouldn't be dropped that way...
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Offline avastnoob

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Re: Avast killing internet speed
« Reply #24 on: December 23, 2007, 07:44:10 PM »
It wasn't an "overinstallation" - it was a complete reformat and fresh install but the problem was still there. Anyway, back with NAV now. Overall it is slower than Avast but 2008 is better tan 2007 and I am getting my full download speed

Offline Lisandro

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Re: Avast killing internet speed
« Reply #25 on: December 24, 2007, 10:40:38 PM »
Anyway, back with NAV now.
Were you trying to use Norton at the same time as avast?
I mean, was NAV preinstalled in this system?
You'll be with a antivirus conflict...
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Offline avastnoob

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Re: Avast killing internet speed
« Reply #26 on: December 25, 2007, 06:51:43 PM »
No I wasn't also using NAV

Format HDD, install win XP SP2 & mobo/graphics/sound drivers with IE7, Firefox and Avast/Comodo with no other software. Webshield on gives download speed of about 14 Mb/s but with webshield off it goes up to 19 Mb/s so.....

Format HDD, install win XP SP2 & mobo/graphics/sound drivers with IE7, Firefox and NAV with no other software and download speeds are a constant 19 Mb/s so I have stuck with NAV

Offline Vlk

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Re: Avast killing internet speed
« Reply #27 on: December 25, 2007, 07:34:40 PM »
Most of these issues (or non-issues) are actually related to the router you're using. The TCP protocol has a number of parameters that can be tweaked. The TCP stack in Vista contains a bunch of changes ("improvements") related to this. I'd be quite curious to see the results from a Vista box (using your Internet connection)

Our results show that in a LAN environment, we're able to stream ~260 Mb/s (using an average Windows XP PC).
However, changing the various parameters (buffer size, window size etc.) DOES have an effect on how it performs. This means that on higher connections the default settings may not be ideal (and it would be useful to allow the user to tweak them [which is currently impossible]).


BTW as far as I know, Norton does not have a HTTP scanner so I don't see a reason for using NAV instead of avast (even if you choose to turn WebShield off).

Thanks
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Offline Lisandro

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Re: Avast killing internet speed
« Reply #28 on: December 25, 2007, 08:04:57 PM »
However, changing the various parameters (buffer size, window size etc.) DOES have an effect on how it performs. This means that on higher connections the default settings may not be ideal (and it would be useful to allow the user to tweak them [which is currently impossible]).
Why is it impossible to change the defaults?
Isn't there any tool to do that? Can you suggest one (for Vista)?
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Offline avastnoob

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Re: Avast killing internet speed
« Reply #29 on: January 06, 2008, 12:52:12 PM »
Just thought I'd post an update as over the Xmas period I set up a new laptop for a friend. The laptop was a brand new install of Vista and I then installed Avast. I then ran a few download tests for my own curiosity whilst I had the chance with a Vista machine before I installed any more software

I noticed exactly the same as on my XP machine - webshield causes a 4 to 5 Mb/sec drop in internet speed - i.e. webshield off I was getting around 16 to 17 Mb/s (a bit slower than my XP PC but I am assuming there is a bit of a loss due to the wireless connection) but with webshield on it dropped to around 11 to 13 Mb/s.

I took the router out of the equation but still notice the same drop in speed with web shield active if the machines are connected directly to my cable modem.

My friend only has a basic 2Mb/sec internet connection and is not noticing any discernable difference with webshield on or off
« Last Edit: January 12, 2008, 01:19:38 PM by avastnoob »