empty cache

A cache is temporary memory designed to speed up access to resources. Previously accessed web pages are stored on the disk of the personal computer running the browser. When a user is flipping back and forth between previously accessed pages, the browser retrieves the pages from the local disk rather than from the remote server. Use of cache speeds up retrieval, reduces network traffic and decreases load on the server. ...

"Empty Cache" means to delete the files. They are completely deleted, no further action needs to be taken.

Pro's/Con's It doesn't hurt to delete the cache, and you may find increased page loading when done, due to excessivly sized cache before the delete.

PowerMac G4 867 dual Mac OS X (10.4.3) 20" Cinema Display, Pioneer DVR 107, 1Gig RAM

Hi giwwwy!

Although the process normally won't have ill effects, emptying Caches is usually a troubleshooting procedure, and isn't necessary to do on a regular basis.

Your Mac has several Caches. Which of these are you referring to? Browser Cache, maybe?
Caches store previously accessed information. This expediates the retrieval of that info.
For example, when you visit a Web page, that page is stored in a Cache.
The next time you surf to that page, it will load faster.

Emptying some caches may temporarily slow your Mac's performance, as the Caches will rebuild.

This link gives a more technical explanation Cache - Wikipedia, the free encyclopedia.

More links here Search - Wikipedia, the free encyclopedia.

EDIT: Keith explained it much better than I!

ali b

glwwwy

OS X as well as many applications, write the most frequently used data portions into a cache file so as to speed up their operations. For example the windowing system may write the contents of the root level of your boot drive into a cache file so every time you are opening your boot volume it retrieves the information from there. This will make the opening of this volume appear to be much faster.

Some times, however, caches get corrupt. When this happens applications, including the OS, begin to misbehave. In such cases deleting them can bring back your mac to working order.

Deleting caches will not harm your mac per se, however, you may notice that some operations will appear to be slower as applications or the OS are forced to work harder to retrieve or manipulate some portions of data. With time speed will increase again as caches will be rebuilt.

There are three type of caches: global caches, inside /Library/Caches, which deal with processes common to all users in a setup' user caches, inside /Users/username/Library/Caches/, which deal with the processes related to a specific user and system caches, which deal with system processes.

To delete caches you can do manually from the finder, via command line in single user mode or terminal or with the aid of third party utilities such as Onyx or Tiger Cache cleaner (compatible with previous versions of the OS). If you opt for the Finder or terminal approach make sure you immediately restart your mac after deletion.

Bear in mind that cache deletion must not be seen as a panacea, i.e. the solution to all problems. It is not. Deleting them must be a user's last resort and not a maintenance routine.