Standard guidelines for ideal Web response times (Nielsen 1999, page 42):
0.1 second (one tenth of a second).
Ideal response time. The user doesn’t sense any interruption.
1 second. Highest acceptable response time.
Download times above 1 second interrupt the user experience.
10 seconds. Unacceptable response time.
The user experience is interrupted and the user is likely to leave the site or system.
These numbers are useful for planning server capacity.
Speedy downloads, speedy connections:
Minimize HTML, the number and size of graphics, and multimedia
Use high contrast colors for optimum legibility (black text on white background best)
600 pixels and resizable [although 580 works best on Macs – ed.]