High performance memory has come a long way from its early incarnations. In the DDR2 days 800MHz was the norm with 1066 for the wealthy or performance hungry. With the move to DDR3 for a long time prices were such that performance was almost a secondary consideration compared to how much you could get for your money. However, times have moved on and as DDR3 became more affordable manufacturers started to produce high-performance kits.
These were still in the enthusiast bracket mainly due to the early X58 speed limitations requiring some fine tuning and tweaking to obtain the speed advertised. The introduction of the P55 chipset and LGA1156 socket have greatly altered the landscape.