Load Line Control (LLC), is an electronic circuit designed to maintain close control over the CPU voltage as the load and thus voltage changes based on CPU frequency and power demands. With high powered CPUs, many cores, Turbo and energy saving modes there can be a huge change in the current (amps), required as the CPU changes frequency, loads and temp. Big current fluxuations can cause CPU voltage droop. The LLC circuit tries to keep the CPU voltage at the desired set voltage under all conditions - though this is difficult to do with a wide range of power demands.
Enabling LLC allows the electronics to try and maintain the CPU voltage as accurately as possible. Different mobo makers use different circuitry and BIOS options for this. Generally all you can do is test the various BIOS options while monitoring the CPU voltage say with OCCT stress testing graphing to see which BIOS option appears to work best for your configuration.
Edited by AMD4ME - 6/5/12 at 2:41pm