The speed of computer response to user entries should be appropriate to the transaction involved.
Additional Information:
Appropriate response times for selected activities are shown in Table 2.4. In general, the response should be faster for those transactions perceived by a user to be simple. For example, computer response to a likely control entry, such as NEXT PAGE, should be within 0.5 to 1.0 second; response to other simple entries should be within 2 seconds; error messages should be displayed within 2 seconds.
Table 2.4 Maximum and preferred system response times.