The 8400GS may be showing its age now, but that perhaps works in its favour - it is very cheap to buy now, and for a beginner looking for a quick and effective upgrade to their system, this is a great choice.

As with any graphics card, physical installation is fairly simple - just open up your desktop, plug it in, and providing the correct drivers have been installed beforehand, it should start working immediately - I had no problems when installing mine.

Depending on the PC you have, you will probably see different jumps in performance - personally, installing this card into a HP Pavillion PC, there was a very noticeable improvement in performance - not only was it now able to play some of my favourite games at a respectable frame rate, all processes in general started running more smoothly - such as minimising/maximising windows, switching between screens, and other graphical functions. If you are running Windows Vista or Windows 7 with Aero enabled, you will probably notice this as well. Another good thing about the 8400GS is that the minimum wattage for the PSU (Power Supply Unit) of your PC is only 300W, which is relatively low - meaning you should be able to use this card in your pre-built PC (from Dell, or HP, etc) without needing any further upgrades.