In this case we recommend the latest driver from Intel found here: https://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=23186
You may verify your Intel® wireless adapter and router settings as suggested in the article below. You may also update the router’s firmware even though it is not apparent but just in case of compatibility issue.
I've installed now Windows 8.1 and now I have the same again. On Windows 7 I solved the problem by updating the driver (as you wrote), but now on Windows 8.1 Pro I already updatet the driver but it didnt change anything. I still have these lag spikes every few minutes. On Windows 7 (which I have also installed) I have no problems.
Can someone help please? Thanks.
Just in case, this is the latest driver: https://downloadcenter.intel.com/Detail_Desc.aspx?ProductID=3622&DwnldID=24220
You may want to update the router’s firmware and if you have a dual band router you can try connecting in the 5 GHz band.