High uplink buffer

[Pierluigi Iezzi]

Hey there, i'm having issues with my new adsl. It's very fast, i can download stuffs at 1.5 MB/s, this morning at 2 MB/s, VoIP experience is very good.
I have problem in gaming: It's everything good and smooth, 40-50 ms ping, but i have often lag spikes.
Everything freeze and after 1-2 seconds... i'm dead X_X
Here some tests/values:

line attenuation: 8,3 (up) / 20,5 (down)
SNR: 9,5 (up) / 8,1 (down)

If i run pingtest several times, sometimes i get 20-30 ms jitter.
I ran ICSI Netalyzr and it says i have a high uplink buffer, 2400 ms.

Download and upload speed is ok, ping is ok, no packet loss, line attenuation and SNR seems to be ok.
The only things weird are jitter, that sometimes is 20-30 ms, and uplink buffer (2400 ms).

I tried TCP optimizer with optimal settings, nothing changed.

Oh, i have this problem both on my laptop and desktop, i have Windows 10 Home (laptop) and Windows 19 Pro (desktop).
Both connected via wifi, but i tried with ethernet and nothing changed.

Help me! thank you