Lately when downloading large files from the internet, commonly streaming a video or downloading a large application the transfer speed starts out good - maybe 300-400 kilobytes/second. Then over time (next 15, 30 seconds) it slows down to at little as 75 kilobytes/second. Running a speed test often comes back with good results, but the speed test is done over such a short period of time that it seems to not be a real world test case.
I've heard that if this type of drop-off occurs that it's most likely a router problem. Can you guys confirm or deny this assertion?
In either case, what types of things should I look at to diagnose and resolve this?
Some info about my network:
fairly new Linkysys wifi router
devices experiencing this problem include iPad, iMac, and Apple TV.