Opera

Caching documents allows for faster retrieval and offline browsing of Web contents. You can choose how much space Opera uses to cache documents by pulling down the "Tools" menu (or "Opera" for Mac) and selecting Preferences > Advanced > History. You can set the cache size to be higher, so that more documents can be retrieved from cache and not from external machines.

Please note that a larger cache size might actually slow down older systems. In general, we recommend that users with older systems (early Pentiums and older) set their disk cache to 2 MB and memory cache to automatic or 4 MB.

A very large cache might also cause Opera to take longer to start, if the cache is filled up.

If you enable automatic memory cache, it will take up about 10% of the available RAM on your system.