Wireless Network Stuttering ENTIRE System?

So after almost 2 months of testing on a new system I have finally determined that my wireless network has been the cause of a very strange 'stuttering' problem i have been having. It would trigger during games, playing music, or watching streaming video. This was not "buffering" or "lag" but I would get massive mouse stuttering that would also interrupt any audio playing to the sync of the stuttering. I have had all the hardware tested in this system by my local shop with them benchmarking everything and ultimately being unable to replicate the problem. Second I got it back the stuttering came back (it also connected to their wireless network just fine). I discovered that this was finally the problem today while playing a game and ALT+Tab'ing out to desktop and disconnecting myself from my landlords network (shitty part about this entire thing is, I have had no access to the router or source upstairs, this is a network with about 8 different devices hooked into it so the signal strength never has been great) and the stuttering stopped instantly. I am so relieved to have this problem solved because I have racked my brain trying everything I could think of in troubleshooting the source of the problem. From external USB sources, power supplys, power bars, testing the RAM, testing the Hard Drive you name it.

My question is, why and how could a wireless network card plugged into the mobo stutter my system in this way? The very same Network card connects to other networks with no problems. Has anyone ever heard of a problem like this before? Is there anything that I could try to alter in the router settings to fix this? I do have the IP address for the router so I can go into settings without heading upstairs to physically alter anything

Thanks for the help, I swear I'm not crazy, you would not believe what I have been through with this system (this is one problem out of like 7 on this system)