Does cloud computing perform well? That depends on who you ask. Those using SaaS systems and dealing with standard Web latency can't tell you much about performance.
You need to consider the following performance models, which you can break into three very basic categories:
- Client-oriented
- Cloud-oriented
- Hybrid.
Client-oriented typically SaaS (software as a service), interact with users constantly over the Internet. The issue here is not that the cloud provider is slow, but that there is latency with the constant back-end machine-to-machine conversation that occurs between the SaaS provider and the browser.
Apart from implement an expensive connection between yourself and your SaaS there is very little you can do about this, and doing this would dilute the value and story of SaaS. Client Orientated (SaaS) will not be as quick as on premise solutions but most of the time the end user will nit experience any latency.
Cloud-oriented processing occurs within the cloud. Most infrastructure-as-a-service providers (IaaS) fit into this category. These systems can provide better performance than on-premise solutions because they have access to many more virtualised resources and can allocate those resources dynamically.
Hybrid, The concept is that you can mix and match user interactions with highly scalable and on-demand back-end processing. The trade-off is the more you communicate with the browser, the more latency that's brought into the model. Thus, the approach to the architecture here is to optimize the chatter between the back-end cloud-based servers and the browser. You accomplish this with some old-fashioned distributed application architecture.