Willy they slow down the Solid State Drive's performance? For an example, if I buy a Kingston HyperX 3k 120GB Solid State Drive and use a Windows 8 and three games on it, would it drastically slow down the performance of a Kingston HyperX 3k Solid State Drive?
SSDs slow down over time due to the way they 'defrag' (called trimming and it's quite different but same concept). Not all SSD's do this as well as others. That said, anytime you ise anything it won't be as good as new. However, they are still so much faster than hds that you shouldn't hesitate to get one. Also, you can backup your SSD data, do a secure erase, and the SSD is practically new again.