Weird Problem

[Markuz Nightwind]

I've got a weird problem with my network. At random times (can happen 2-12 times a day) I loose connection randomly for like a few seconds, enough to have every service disconnected at my computer (and every other computer in the house, even if they are wireless connected)
Checking in the router dmesg, it gets an eth0: link down and then it reboots the eth0. I've tried changing my router (I had a D-LINK 2740b modem router that gave the very same eth0 down issue) and now switched to a Bufalo wzr-hp-g300nh2 running Gargoyle 1.5.10 and bridged to a simple modem with PPPoE.

I've formatted my computer, I've changed ethernet cable but still the problem is present, so please give me an hint on what it could be (

Here's the paste of dmesg http://tinypaste.net/GOWOrYd9

Thanks in advance