This is the single most important performance dimension. It's worth a full twenty points.

This dimension is important because load speed determines whether or not people who are interested in your Web site stay around to find out if it's any good. Usability studies tell us that consumers generally don't wait for slow sites to load. Instead, they click off to something else.

Here's the standard. Your site should load in ten seconds or less for a first-time user, using a dial-up modem. Let's look at those three conditions.

The ten seconds or less standard is derived from usability studies and also from behavioral science research into how long North Americans will comfortably wait for something to happen. That something might be how long they’ll wait through silence in a conversation without saying something. It might be how long they’ll let a phone ring before they hang up. And, it might be how long they’ll wait for your Web site to load.