I know we mentioned this earlier on already. Some of Gigabyte's X58 motherboards did not carry SLI support. Gigabyte (as far as we know) made that call for some boards a while ago as for each SLI X58 motherboard a 5 USD license fee needs to be paid to NVIDIA.
Gigbyte now officially announced that if you can pick up a BIOS and get that fixed.
Taipei, Taiwan, April, 2009