Some Intel 975X motherboards are capable of handling Scalable Link Interface, and under Windows there are modified drivers that allow SLI to operate on the i975X Chipset and other Intel Chipsets. However, I just wanted to pass along that the latest NVIDIA Linux drivers DO NOT support the i975X Chipset with SLI. Attempting to enable SLI or MultiGPU from the NVIDIA 1.0-9626 display drivers will fail.

Quote Originally Posted by X log
(**) NVIDIA(0): Option "SLI" "on"
(**) NVIDIA(0): Enabling RENDER acceleration
(**) NVIDIA(0): NVIDIA SLI auto-select rendering option.
(WW) NVIDIA(0): DamageEvents are not currently compatible with SLI. Disabling
(WW) NVIDIA(0): DamageEvents.
(II) NVIDIA(0): Support for GLX with the Damage and Composite X extensions is
(II) NVIDIA(0): enabled.
(EE) NVIDIA(0): Failed to find a valid SLI configuration!
(EE) NVIDIA(0): Invalid SLI configuration 1 of 1:
(EE) NVIDIA(0): GPUs:
(EE) NVIDIA(0): 1) NVIDIA GPU at PCI:1:0:0
(EE) NVIDIA(0): 2) NVIDIA GPU at PCI:2:0:0
(EE) NVIDIA(0): Errors:
(EE) NVIDIA(0): - Chipset not approved for SLI
(WW) NVIDIA(0): Failed to find a valid SLI configuration for the NVIDIA
(WW) NVIDIA(0): graphics device PCI:1:0:0. Only one GPU will be used for
(WW) NVIDIA(0): this X screen. Please see Appendix W: SLI and MultiGPU
(WW) NVIDIA(0): FrameRendering in the README for troubleshooting
(WW) NVIDIA(0): suggestions.