Via Extremetech: System memory is often the forgotten cousin among components when you're building a new PC. A lot of PC builders just buy whatever's out there, as long as it works in their systems. Some enthusiasts take the opposite route. They get expensive ultra-high-frequency or low-latency memory, hoping it will give them a big performance boost.
Most major memory manufacturers now offer special low-latency memory. Kingston has a low-latency line of their HyperX DDR400 RAM. Crucial offers a high-performance line called Ballistix. OCZ Technologies has sold specialized low-latency RAM for a long time. And an "LL" designation shows up in Corsair's XMS memory line to indicate this characteristic.
You can pay from 30 to 100 percent more for these low-latency offerings, but are they worth the extra money? We examine the effects of low-latency memory on two high-end systems to determine its value to PC builders. (continue reading here)