While text content may be drawn from a database, the graphics are often the same between users and between pages on the same site. Since graphics represent a more significant portion of the data downloaded, a web cache can still have a dramatic impact. Finally, there is the issue of network design and overall throughput. For those on faster networks, it is an issue. Even with Fast Ethernet links, the cache introduces latency and overhead in processing web requests.
Most caches have a peak throughput of something less than the physical network connection.
In situations with high performance networks, benchmark the cache carefully. The performance impact Cache performance is highly dependent upon the exact characteristics of web usage at your site. The more users sharing a single cache server, the greater the potential benefit. A small network of users with a diverse set of interests may see minimal gain from a cache as they have very little overlap in browsing activity. This means that at least a fourth of http requests will be handled by data from the cache, reducing web traffic on your Internet connection.