Norton 360 slowing internet connections

It seems every time Norton 360 does a  product update, my internet speed decreases. I have contacted my ISP and they checked the speed remotely and it shows 400+ mbps. Also, on my Iphone I am getting 400+, wireless. 

My PC, wired connection, is barely getting 130mbps. It was over 200 three weeks ago. Been degrading ever since the last update.

I am running Win7 64 bit on an older PC. I have another PC that is doing the same thing. I have reset my modem twice to no avail. Checked startup files, nothing unusual. No major changes have been made to either PC

[Edit: Clarified subject]