I've had this complaint 3 times in past. Here's the check process:
When TFL is slow, try loading another favorite site instead....I usually open a second Browser window for this, in order to keep TFL's unread posts from updating before I read 'em. If the other site is also slow, it ain't TFL; it's either the Internet or your ISP.
Each time in past it's not been TFL. TabNet, our server, has the highest thruput available.