Quote Originally Posted by Origin_Unknown View Post
what is the main reason for more cache? is it for faster read / write?
In the simplest case cache is the fastest source a system can read from. It does not speed up the initial read of data, but it speeds up subsequent data requests that are still in cache. The more cache you have, the greater chance that your next read request will already be in cache and, hence, read faster.

So ultimately even if the hardware is otherwise identical on two RAID controllers, the one with more cache is going to end up feeling smoother and faster in environments with repetitive data access (eg. home computers, small servers).

Plus e-peen obviously.