Let's just understand what a cache is;
It's a place where stuff is set aside for later use. In archaelogical terms, this can refer to hordes of treasure. Its meaning in computing terms is not really so different, since caches are not necessarily quicker than the original source. For example, the biggest cache you have on your computer is the page/swap file.
Pentium pros had up to 2Mb of cache, like Xeons. This cache memory is what makes the processors so expensive, since it's much faster than conventional RAM, but not as fast as the processor. It's a handy place for the processor to stick data that it's not using until it does need it, because it can get at it MORE quickly than other storage areas.
Xeon processors have different architectures, that suits them well to intensive operations, such as application servers. Single user audio work will not benefit as much from using this architecture as it would from using two processors under an operating system that supports SMP, and large (at least 512MB) RAM. The cost/performance ratio does not justify buying a Xeon with 512k cache over a PIII/IV with the same amount.
For "Flawless" audio work, consider a professional sound card setup. Depending on your budget, you should investigate (at the low end) Turtle Beach, (in the middle - high range) Event, and at the top, Digidesign. If you are thinking about 2 x Xeons with 2Mb cache each, maybe you've got the budget for Pro Tools. These require next to no processor time, and are recording industry standard (but beyond the reach of most mortals!)
The internet cache on most computers is set within Internet Explorer. You can safely delete all of the files contained in the Temporary Internet Files folder - it's just a storage area, as I described above. Also check your c:\windows folder for files called *.tmp (where * is a wildcard), and any folders called temp or files that begin with a tilde (~). All of this can be deleted, and will help speed up your computer. Check also my FAQ on Virtual Memory.
Caches are very useful, but a trade-off. If a cache becomes too full, you can't put anything else into it, which will have the reverse effect, ie the system will slow down. Memory caches clear themselves when you reboot - which is why rebooting can clear many issues. Physical caches of files, however, must eventually be cleared out manually, if the operating system is not sufficiently configured to do the job itself (ie Windows ;-)).
I hope this is helpful to all CitrixEngineer@yahoo.co.uk