Please help, normal ping, but so so much lag. Over the last week I've had a completely normal ping (~15-25) but every 10 seconds or so I'll get some crippling lag that sets me back a couple of seconds.

I tried lowering my graphics settings to the absolute minimum, and it made no difference at all. I have also re-installed TF2 and the problem carried on.

Any help? Because this is starting to make the game unplayable and I don't know how I'd spend my free time without TF2.