I've been stuck with horrible reoccurring latency spikes for a month now. The lag spikes happen about every 4 minutes and ping tests show that it ranges from 600-800ms ping. I finally narrowed down the causes, and it was my brother's laptop since there are no lagspikes only when his acer laptop is not connected to the internet. Whenever the laptop is connected to the internet, everyone thing else connected to the router experiences frequent lag spikes, making online gaming VERY annoying. At first I thought it was a wireless issue so I tested it with a wired connection. Needless to say, that didn't help as all the other computers connected to our router still experienced frequent lag spikes until we removed the ethernet cord attached to my brother's laptop. Does anyone know what can be causing this issue? is there a way to test and find the source that's making the laptop cause lag to every other computer when it's connected to the internet? The issue started about a month ago and he does not have a system restore point. It's also not a bandwitdh issue since he's not downloading or uploading anything. The laptop is using windows 7 and is currently connected via wired connection. (wireless is turned off on the router and adapter)

There is a piece of software or some process that is running on the laptop. You can download tools @ http://technet.microsoft.com/en-us/sysinternals/default to help analyze the problem. It is virtually impossible to say exactly what is causing the problem without some analysis and some trouble shooting.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thank you Rick, but it seems like I've solved the problem. I shut off the TCP IPv6 option on my brother's laptop and now there seems to be no more lag. Can anyone tell me why?