Ping spikes with WNDR3700 V4 wireless router.

When playing Counter Strike:Global Offensive, I usually get a constant 30-40 ping but recently it has jumped to about 200 every 10 seconds, each spike lasting about 4 seconds. I am using a Netgear WNDR3700 V4. The router is in my basement and I am 2 floors above it on my computer. Although this is a longer distance, it has not been a problem before. I am using the 5ghz network, me being the only device connected to that network. My whole family has their devices on the 2.4ghz network and there is one PC that is connected to ethernet. If anyone could tell me what is wrong and/or what settings I need to change, that would be greatly appreciated!