Lag spikes while playing an fps online (quake live)

[pasqoo]

Hi, I'm having an issue with connection stability while gaming online.

My card chipset is: Atheros Communications Inc. AR9287 Wireless Network Adapter (PCI-Express) (rev 01)
I got Linux Mint 13 Maya 64bit Mate edition.

First issue (already solved), while playing I lagged a lot, until the server disconnected me (due to inactivity).
Doing ping in terminal would give me pings of SECONDS, multiple pipes... etc.
This wasn't a new issue to me, I had it in past with debian testing.
I solved this by installing compat-wireless (the last stable release, I only selected and compiled the ath9k driver with the script included).

Now, the only issue which is still present, is that sometimes (every X minutes, I have to time it better, it's like every minute or so) the lagometer (it's a part of fps UIs which shows the stability of the connection, wikipedia) shows red spikes (which is bad, normally it's green) and I get very bad lag. It stays like this for like 2-3 seconds then the connection returns normal and the lagometer shows only the green bar.

Wikipedia says: "Red bars mean that the frame has not arrived on time"
I would interpret this behaviour as packet loss...

The first thing to check would be to close all the applications, right? But while I play I got only Dropbox and UpdateManager icons in my system tray (and dropbox sync stays Paused while I play).

Is there a way to check what happens to my network while I play? Like some logs... So I can analyze what happens in my pc when those red spikes happen in my lagometer... maybe there's some application using my connection in background.

Thanks

EDIT: adding screens for when it is STABLE and when it is LAGGING.