XFX uses the standard Phoenix Award BIOS on their nForce 790i Ultra SLI board. The BIOS does have quite a few tweaks available for the overclocker, as it allows FSB, Voltage, Memory, and other tweaking of the system to get the highest overclock possible from a CPU. The Award BIOS is split into four main menus: Standard CMOS, Advanced BIOS, Advanced Chipset Features and Integrated Peripherals. The other menus offer control over the Power Management and PnP/PCI Configurations but don’t affect overclocking.

Overclocking is done in the Advanced Chipset Features menu. Submenus here include System clocks, FSB and Memory Config, CPU Config, System Voltages, NVMEM memory test. The AwardBIOS has some new settings which should help the overclocker: Load timing/voltage set (which allow the BIOS to set according to one of three profiles), and Save timing/voltage set (which allows you to create profiles).

System Clocks is where the CPU multiplier can be modified (6-8 in the case of our 2.66GHz E6750 CPU). The PCIe slots’ frequency can also be modified from this menu from 100-200MHz. The SPP/MCP Ref Clock MHz can be modified here from 200MHz-500MHz in 2MHz increments. The HT Multiplier can be set from 1x-5x in both directions from this menu.

The FSB and Memory Configuration menu is where you can change the FSB and memory settings. One thing I would recommend is you change the FSB-Memory Clock mode to Unlinked so you can run the memory independent of the FSB. FSB can be set from 400-2800 by entering a DEC number. Note that it is actual FSB that you are setting, not CPU speed, so 2800MHz FSB gives a lot of room to maneuver. Memory MHz can be set from 400-2500MHz by entering a DEC number. The last overclocking submenu is the Memory Timing Setting submenu which allows you to set the various memory parameters.