There has a been a lot of work in this area. Look up discussions around Net Promoter Score (NPS). There's a general belief that page load time has a rather dire

There has a been a lot of work in this area. Look up discussions around Net Promoter Score (NPS). There's a general belief that page load time has a rather direct relationship with user happiness and how likely they are to recommend your service. It's not my area of expertise but I think it's something like 2s on a decent connection. No action should take longer than that. For example: * Page should load to a useful state (could still be background tasks) in under 2s * Clicking a link should take me to the next page and it should be useful in under 2s * Making a change to a config item and saving the update should complete in under 2s If your service can do that, you customers will feel like your system is fast. On the other hand, this is generally considered a technical crowd and we probably look at resource consumption. A site that eats 25% of one of my CPUs and requires 128M of RAM just to load is going to check my box for bloated.