About 5 days ago I noticed a significant slow down in loading web pages. In some cases, I see a blank white screen for up to a minute before the page loads. In others, the page never loads at all. And sometimes they do load very quickly as expected. This happens with my iMac that is connected to an Airport Extreme router via ethernet, as well as my Macbook Air connected via Wifi. I have a high speed Comcast/Xfinity cable internet connection: Blast 250Mbps. I tried connecting my iMac directly to the cable model (Arris Surfboard SB6183), and there is no problem. Download speed was 300Mbps and upload 30Mbps. I then hooked up my Airport Extreme router again, and connected the iMac to the router via Ethernet. Download speed dropped to 100Mbps! I then did a speed test with my Macbook Air which is connected via Wifi and the Airport Extreme router. Download speed dropped to 35 Mbps. So it seems the issue may be with the Airport Express. It's not a wireless problem, because as you can see the download speed dropped from 300Mbps when connected directly to the model to 100Mbps when connected to the Airport Extreme, and then to 35Mbps when connected wirelessly. How do I troubleshoot/fix this?