Problem Dell 2350 Router

Hi, I'm having some trouble using the router. I don't have any problems when I'm just surfing the web or anything like that... but I run into some major lag spikes when I try to play online games. I've noticed that I don't get these spikes when I'm playing with an ethernet adapter. The trouble is that I don't have access to one for this computer. I have Wireless Zero Config. disabled which is supposed to help for this issue but, I still encounter the problem. Any help is greatly appreciated, thank you.