Not all Intel X58 motherboards support SLI
 

Back in late August, Nvidia decided to give Intel and its partner a chance to implement SLI on X58 boards. Nvidia offered two options, hardware SLI support with its Nforce 200 chip, or software support for a nominal fee. Additionally, some sources suggested that Nvidia charges mainboard manufacturers around $5 per unit for its SLI licenses.

It has been known for several months now that most X58 boards support both Nvidia SLI and ATi CrossFire technologies. According to a recent report, however, one Gigabyte user over at the Guru3D Forums has reported that the GA-EX58-DS4 he purchased does not support SLI but only supports CrossFire.

According to an article from DVHardware written back in October, only the Gigabyte GA-EX58-UD5P, GA-EX58-Extreme , and GA-EX58-UD5P were confirmed to receive X58 SLI licensing.

http://www.fudzilla.com/index.php?op...70&It emid=37