I have a network in my apartment with two wired computers to my Linksys router with DD-WRT installed and one wireless laptop. One of the two computers that is hooked up through the cable has Windows MCE (XP) installed on where I record tv. The laptop is also set up with MCE to act as a media receiver.
The problem I am having is that when the laptop is streaming video, it will work fine sometimes, and then suddenly it will get really choppy and not stream correctly. I have disabled any sort of encryption and firewalls, and tried putting my router on both channels 1 and 11, but the problem continues. The only thing I can think of is the laptop wireless card is overheating, but I have tried turning off the computer and putting a fan right next to it for about a half hour, and when I turned it on again it still lagged.
You may want to check with your ISP. Often when you start using a lot of bandwidth they will cut your download speed. If this is the case you are pretty much powerless to do anything about it. Most cable companies and the majority of DSL companies do this.
Try running this test:
ping google.com -l 1024 -t
Start running it before you begin streaming. as you stream a video it will drop some as you are using a good portion of your bandwidth. When everything gets choppy look at it again and you will see that the time will increase dramatically.
Also, if you do not have at least 1MB of download speed you may just be buffering enough of the video to make it play for a bit and then the connection cannot catch up. You can find out how much bandwidth you have from your ISP or by running a network speed test.