Work laptop is wifi nuke

I have a fairly recent macbook pro (osx 10.8.3), and ever since I brought it into my house it has been causing wifi problems. Just by being connected, it cuts the download speed of every computer in the house from around 11 to around 3 mb/s. I've monitored its connection through activity monitor, and there are no abnormal upload or download behaviors. Just by being connected it shuts down the wifi. It doesn't even hog it, it just kills it.

Any ideas as to what may be causing it?

There is some backup software and while it does cause upload and download spikes the problems persist every second between its backup (a 6 hour interval).

Can't really offer you much help without some more information. How many devices do you have at home that are connecting to your WiFi? And, assuming you're using a router, how about telling us which one you have and how old is it?

Also, what happens when you disconnect everything else and just run your new MacBook Pro off the WiFi? What kind of speed are you getting that way?

Also do you get the same results if you connect it by ethernet and disable wifi on the MBP

It sounds as if ... somehow ... the work notebook's Airport card is set at 802.11b speed, and thus dragging your whole network down to that speed.

I was thinking something similar - connecting by ethernet and disabling wifi would help determine if it's a wifi issue or a process running on the Mac that's at fault