About a month ago I started having an issue with my internet connection where for 3-5 minutes at a time I would get the "Problem Loading Page" "Server Not Found" message. After a period of time it will go away and pages will be found and load normally, but the problem comes back multiple times per hour. Switching browsers (IE, Fox, Chrome) has no effect. I have 3 different computers that I run through my modem (Motorola Surfboard SBG6580 Wireless Cable Modem Gateway) using cords and wireless and they all have the same problems. I have restarted the cable modem well over a hundred times and about the same for the computers. I have tried only having 1 computer connected to the gateway at a time and had similar results. If I am downloading files I do so at full speeds and if I am playing any kind of online game I never notice any kind of issue. I've also disconnected my main computer and brought it to a friends house and hard connected to his router and had perfect internet for over 4 hours.
I have comcast cable internet and like I said about a month or so ago I did not have any of these problems.
If I can successfully connect to speedtest.net and run the test I consistently get results of 10 ms ping, 25 Mbps download, and 3.3 Mbps upload. The only time I can't produce these results is when I am in a "Problem Loading Page" time and the speedtest.net page won't load.
If it helps, there are also times where I can successfully connect to a page but not all of the pictures will load, as if I half-connected to the page.
Any help or advice would be greatly appreciated. I am more than happy to adjust settings and provide any more useful information!