I've been going around, and around with Comcast lately, on a issue which began a couple months ago - sometime in early April I believe. I'm paying for the "Extreme 105" connection.
They replaced major equipment in the Seattle/Bellevue area - and ever since then, page load times have been very inconsistent, and images load slowly. During these times, the browser occasionally says "resolving host" - and then connects, with on-page elements loading much slower than before.
I've also noted that when doing traceroutes, there are more local "hops" than before these issues occured. But, speed tests appear perfectly normal - even though page elements loading time is noticably slower than before.
I'm hoping there are others out there who can confirm similar symptoms.