Constant Lag Spikes

I’m getting lag spikes every so often no matter what server I join. Where the server is hosted doesn’t matter because I have a decent connection to it (such as one hosted in the UK I can get around 80 ping (I live in the US)).
My internet speeds are shown here http://www.speedtest.net/my-result/3592521434
Processor: Intel i7-3770 @ 3.40GHz
Graphics card: NVIDIA GeForce GT640 2GB
RAM: 12GB
I really shouldn’t be having any problems running this game even at recommended settings. I tried reinstalling GMod, removing all addons, turning off Windows Aero extensions, verifying integrity of game cache, and messing around with my graphical settings. None of these worked and this started happening about 2 weeks ago. This even happens on servers I never had a single problem with joining and keeping a stable connection to.

I posted a youtube video so hopefully there can be more information about what’s happening.

It is a connecton problem, your specs are irrevelant.

Does this happen in other multiplayer games?
In Source Engine/Valve games, such as TF2, L4D, CS?

Indeed it does, TF2 and Planetside 2. Also I was just posting specs to show that my computer isn’t the problem for the lag.

Then it isn’t a problem with the game either. Check your internet connection usage. Make sure you don’t run network heavy applications when gaming. Also check your firewall settings.

What specifically should I be looking for? I run nothing but Garry’s Mod but this problem still happens.