Hi, like the title says, I sometimes observe an extreme amount of lost packets, like 40%, paired with 3000-4000 ms lag.

I play on a laptop: win 8.1 64bit, 8GB ram, i7 4210U, nvidia 840M. This notebook does its job well, with no frame rate issues.
Connection is wireless, speedtest reports 7+ mbps. I cannot try wired because router is in another apartment. Router is On-Networks N300RM.


ISSUE DESCRIPTION
I installed the game a couple months ago and it worked nicely, then suddenly I started to have lag issues.
I can just play fine some times, with 130ms lag and <1% packet loss.
But next time, as soon as I log in, packet loss starts to increase constantly up to ~15%, ranging from 5 to 40%. Game is just unplayable, can't even browse AH reliably.
Internet connection is fine. I can watch youtube and download files with no problems while DDO is closed. If I open DDO and it lags, internet browsing is not affected at all and smooth as usual.

I checked windows firewall, both dndclient and turbinelauncher are listed among exceptions.
I tried to add DDO ports to router firewall, too, 9000-9013 and 2900-2913 TCP/UDP, but with no improvements.
I somewhat expected there would have been no improvements, given that I didn't need to open ports to play smoothly last month, so maybe it is unrelated.
If I check ports with http://www.yougetsignal.com/tools/open-ports/ it still says they're closed though, and I can't figure why.
This image shows router firewall panel and it should be done right. It's in italian but it should be understandable (http://s16.postimg.org/vwb1lcqg5/N300_RM.png).

What is strange is, if I play in windowed mode, packet loss ranges from 2 to 5% with 400-1000ms lag and the game is somewhat playable, although frustrating. This could be a coincidence, though.

I've just no idea what to do. Last year I stopped playing DDO because I encountered the very same problem, but on another PC and with another connection. That time was a win7 64 bit, phenom II 550 with radeon 5770 and 4GB ram, that time too on a wireless connection.
I could be especially unlucky, or maybe I've to configure something...

Next thing I'll do is to start windows in safe mode and see if packet loss is still high.
Meanwhile, if you have any advices, they would be much appreciated. Thank you