The following bins of responsiveness (i.e. response times) based on HCI research at Carnegie Mellon University resonnate with me:
- Crisp: < 150 ms;
- Noticeable to annoying: 150 ms to one second;
- Annoying: one to two seconds;
- Unacceptable: two to five seconds; and
- Unusable: > five seconds.
The context in which these bins were described appears in the March 2006 issues of IEEE Computer: “Quantifying Interactive User Experience on Thin Clients.”-Craig