When I searched for this exact problem, I found a lot of threads, but none which could explain the problem (and I found very few people on those threads were helped with the answers there either, most answers blaming it on external things). I'm convinced the problem is with Windows 7, since the router/modem and all peripherals are the exact same for this computer as my old computer. The whole computer is much improved over the old one. I first noticed the problem after my old motrherboard gave up, and I was given a laptop to use while they put together my new system. The laptop ran windows 7 and the internet lagged. At that point I didn't think much of it, while more modern than my comp, it was still a dated laptop and I figured that was the problem. But the problem persisted with my new computer. The only difference so far being that I'm running windows 7 over windows Vista.
Its the only computer in the house as well.
The problem is visible in online games and communication programs like MSN live, where a lag will suddenly occur, sometimes lasting well over half a minute. Its quite disturbing that my old computer could handle these simple tasks so well, and this greatly superior system can't, solely because its running windows 7.
I hope someone can think of what exactly in the software is causing this and there is an easy solution (something i can turn off).
Any help much appreciated ...