how slow is too slow?

Site speed is usually measured in the seconds it takes a single page to load over a given internet connection (56K modems are usually the lowest-common denominator). This speed is then translated into a rough K-size, so the production team can stick to the guidelines without speed-testing every page.

A good rule of thumb is that your pages should load in less than 12 seconds for users on a 28.8K modem (that's about 8 seconds on a 56K). But every site has to decide for itself how fast its pages should be. Sites aimed at utility search engines, for example need to be whip-fast. While online magazines and art galleries can afford to be a bit slower.

Between the moment the user clicks on a link and the moment the page appears on her screen, a lot of things have to happen. And they all slow you down.

Expectations will often vary even within a single site. The home page is expected to be the fastest (though often it isn't), so you can pull visitors into the site. Subsequent pages can be a bit slower since users are more engaged and more likely to wait.

Now, that isn't to say users won't wait for anything. If you have an interactive game or a short film, users will expect to wait longer. But even then, you need to get them in the door first. Once they understand your site's content, and decide it's something worth waiting for, that's when you can hit them with a long download. But not before.

Check your speed

NetMechanic

http://www.netmechanic.com