incrediBILL - 5:18 pm on Jan 1, 2011 (gmt 0)
While SSD is screaming fast compared to a standard HDD, most people overlook the simple fact that a couple of GB of RAM used as a smart RAM disk cache coupled with a high end HDD can easily put SSD to shame when it comes to sheer speed and performance.
Most parts of a website that generate the most common bulk of bandwidth usage are typically static such as the images, css files, .js files, etc. which are best served from cache in the first place.
See Squid for starters: [squid-cache.org...]
Even databases tend to read/write mostly from a lot of common sectors that when cached in a RAM drive speed up the entire system significantly.
There's no write limit either, so it's a good long term choice.
Even if you do go with SSD, the combo of SSD and a RAM drive are even more impressive and an intelligent write-back cache which avoids rewriting sectors that didn't change (thanks to sloppy software) could even extend the life of the SSD.
If you're using a Windows server, SuperSpeed is a decent choice: [superspeed.com...]