Actually I have the same issue. I installed the new Creative Cloud, it so long time! I jumped from 1 wifi to the other, tried the 2.4GHz and the 5GHz, pairing with my phone, nothing helped. Speedtest usually gave a 90MB result, since installed I only have around 10MB accross all my devices (Iphone, Ipad). I disconnect the Mac from the Wifi and all devices are back at 90MB. I deinstalled CC and the speed was back!