Dramatic internet speed decrease after KTS 2019 install [UN-CROSS-POSTED]

Userlevel 1
I reimaged my system recently and measured my internet speed on a complete clean system. My ISP declared my fiber to deliver 500 Mbps and I can get even more - 510-530 Mbps.

My OS: Windows 10 Pro x64 1809,
My KTS: (d)

Unfortunately right after KTS install I'm getting only 80-120 Mbps speed! Nothing else has been modified in the OS, just KTS installed. When I exit KTS and re-measure, I'm getting up to 300 Mbps. It's still far from the full throughput, but much better.

Anyway, it seems clear it's KTS that obstructs the network, however I have no idea how. I've already disabled all (or most) of the settings that might have impacted traffic speed:
  • injecting javascript to screen pages
  • limiting traffic at metered connections
  • screening encrypted connections
  • auto-detecting proxy
None of those settings has improved my connection speed at all. Does anyone has any ideas what else can be tried?

I remember I did the same test few months back with KTS 2018 and even though the network speed got a bit down (by say 10%) there was no such disaster as with KTS 2019. I'm really thinking on switching into some other security provider...

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44 replies

Userlevel 7
Badge +9
Hi, @mikolajek

After you install a Kaspersky Lab product, your Internet connection may get slower according to some measurement apps or websites.

All Internet traffic goes through the Kaspersky Lab product's filter, and its work can be misinterpreted when measuring traffic download or upload speed.

To measure the real Internet connection speed, try downloading a file bigger than 1000 MB using either a download manager or a torrent client. Internet connection speed also depends on the Internet channel load and node location. If Internet connection speed is slower than it should be, try testing your Internet connection on different websites in different time of the day.

If the measurements still show slow Internet connection speed, please create a request to Kaspersky Lab Technical Support via My Kaspersky. Describe your problem in all details and attach screenshots showing Internet speed decrease. For information on how to use My Kaspersky, please refer to the Online Help page.
Userlevel 1
Hi Friend,

Yes, I'm aware the speed will decrease a bit (as mentioned my experience with KTS 2018), but what happens here is a true disaster.

I'm typically using speedtest.net to measure my speed and also my ISP's dedicated tool - they have always given quite comparable results (the difference was +/- 5% only). I've just downloaded a 1GB test file from https://www.thinkbroadband.com/download and I can see that the speed was only approx 25-30 Mbps.

The mesurements I quoted were made this morning and tests before and after KTS installation were made one after the other, so it's not some peek time speed problem or anything else. I've specifically waited with this to Monday morning, to avoid some test blurs related to heavier weekend internet usage.

How can I fully disable KTS internet filter to see if the speed improves then?
Userlevel 1
Have the same issue and just posted on the Community as well. You can review a bunch of posts submitted to the legacy forum, and apply the enhancements advised there. They haven't helped in my case, but maybe they will help in yours.

I do still believe it's a KTS 2019 issue - I didn't have any issues with the previous versions.
Userlevel 7
Badge +9
In Windows 10, the Kaspersky Anti-Virus NDIS Filter driver is hidden, and it is impossible to check whether it is installed or not., as well as to delete it.
Try to find the problem component Kaspersky Total Security by disconnected them one by one.
Userlevel 7
Badge +2
Hi, as well as all the above posts.
Please add a GSI Log with your report.
Userlevel 1
OK, understood.

Getting back to your first response: are you saying that after KTS installation the internet speed is actually more or less the same, only the speed measurement results are somehow falsified?

If so, is there any reliable tool that is not affected by the KTS driver and can be used for this purpose?
Userlevel 7
Badge +9
As I wrote above, you need to compare the download time for one large file (1000 MB and above) with the antivirus turned on and the antivirus turned off using the downloaded manager or torrent client.
Userlevel 1
Roger that!

So here are the speeds of downloading 1GB test file from https://www.thinkbroadband.com/download:

with KTS 2019 OFF:
  • top speed - 18 MB/s -> 144 Mbps
  • average speed - 12 MB/s -> 88 Mbps
with KTS 2019 ON:
  • top speed - 9 MB/s -> 72 Mbps
  • average speed - 7 MB/s -> 56 Mbps
Obviosuly the bottleneck in this case is with the server, not with the client, but still getting up to almost 150 Mbps is good enough for me. It definitely looks that KTS 2019 is seriously impacting the link speed, and I doubt that 50% speed reduction is something that anyone would accept.
Userlevel 7
Badge +8
I've tried that 1GB download test with KTS2020 (the last RC, that last week has been signed to TR, so will be the final)...

My connection: optical fiber 100 MBits/s (symmetric).

I've used FireFox 66.0.2 (x64), and, except for a few seconds that went down to about 7,4MBytes/s, it remained most of the time in 9'2MBytes/s ~ 10MBytes/s...

But it's true that in previous builds K2017 ~ K2018 I know users from others forums that complained because Kaspersky cut down their connections of more than 500MB and They never got speeds near 500MB even in direct downloads, so the Kaspersky issue should be tested with higher speed connections...
Userlevel 1
Thanks for confirming this, @harlan4096!

This may be indeed a case of higher-speed connections. The mentioned test with KTS 2018 made early 2018 was done when my connection speed was 256 Mbps and I got it upgraded in mid-2018.

Anyway, it's another corroborative item suggesting something is wrong with KTS itself 😐,,,
Userlevel 1
@KarDip - how do you attach non-media files in the new community? All I can see is an option to add image / video / link - none of those accepts zip archives.
Userlevel 7
Badge +8
Try with "Upload files" button -> an arrow up...
Userlevel 1
Hmmm.... @harlan4096, shoot me but I can't see such option...

Userlevel 7
Badge +2
Okay you could be missing upload.
This forum platform is new and we are still learning to use it.
Put zip in below URL.
Copy and paste easy read link back here.
Userlevel 1
No worries, @KarDip!

Here's my report: https://www.getsysteminfo.com/report/d4c1e4f4a6448952e1663a4f318f4058
Userlevel 7
Badge +2
Okay @mikolajek, now Kaspersky experts will now look at it and get back to you.
Userlevel 7
Badge +8
@mikolajek: it seems I have this feature because I'm Mod, but standard users don't have it...
Userlevel 7
Badge +5
Hello mikolajek,

I collected more than a few contemporaneous posts and replies that were cross posted in two different topic threads at almost the same time. Please help prevent chaos. Please do not cross post same issue in multiple topic threads.
Hey everyone try this if you are having a speed drop

Kaspersky software > Settings > Additional > Network > Limited traffic on metered connections > Untick.

Also if this has not fully fixed it and your not using a proxy server etc:

Kaspersky software > Settings > Additional > Network > Proxy server settings > Do not use proxy server > Untick > Save,
Userlevel 1
Thanks, @BeanSlappers, I've already got both those tweaked and still no luck...

I have the impression that KTS driver/filter is doing this lousy job. I tried disabling individual KTS modules to see if there was any speed difference, and there was none. The only "solution" is to completely exit application (then I can get 60% of my nominal link speed) or completely uninstall it (then 100% is back). However the uninstallation.... You know...
That is really strange, because I personally have 1Gbps fiber, and I am not having problems with it.

Have you rebooted your router?

What is your system specs?
Userlevel 1
@BeanSlappers, oh sure - I've played with my whole network infrastructure for a long time, with no effect again.

I'm running Dell XPS 9360, with i7-7500U, 16GB RAM, 512GD SSD. The bottleneck could be the Realtek network card, but 1. I've also tweaked its parameters, and 2. the issue appeared somewhere with KTS 2019 (unfortunately I can't say which build), as in the past I had no throughput problems with this card.
Sunmit a ticket to tech support, because it shouldn't be happening to that extent.

Another though have you asked your ISP about the speed drop?

But as I said before it shouldn't be that bad of a drop.
Userlevel 7
Badge +2
I agree with Bean Slappers, maybe check with your IP Providers and get them to check your connection and speed to Router.
We seem to have no issues with internet speed with Kaspersky Internet Security 2019 installed on all home computers.
Userlevel 1
I had a technician visiting me last week on this issue and he confirmed everything was fine.

Moreover, I have my business laptop (with another security suite) also cable-connected to my router and I can get the full speed on it.

Finally, as I said - I did several speed test before I installed KTS and after doing so. In the meantime there were no other installations, updates or other configuration changes. KTS seems then to be the only culprit. It's possible it can be an isolated situation, but I do believe it needs to be validated by Kaspersky Support.

I've placed my support request over 2 days ago and till now, no engineer has even been assigned to review it 😒