i am also having this issue with a Q6700 processor and nvidia 750i SLI chipset (core 2 quad on asus p5n-d mobo)
also running Q6600 and nvidia 780sli....
Found the following in Windowsupdate.log
2013-10-18 20:48:31:178 904 ea4 Driver Matched driver to device PCI\VEN_10DE&DEV_0272&SUBSYS_73801462&REV_A3
2013-10-18 20:48:31:178 904 ea4 Driver Status: 0x1802000, ProblemNumber: 00000000
2013-10-18 20:48:31:178 904 ea4 Driver Matched driver to device PCI\VEN_10DE&DEV_0270&SUBSYS_73801462&REV_A2
2013-10-18 20:48:31:178 904 ea4 Driver Status: 0x1802000, ProblemNumber: 00000000
This device is the nForce Memory Controller
I checked nVidia's site...and found the following:
>>>>Driver support for NVIDIA® nForce ™ motherboard chipsets and their components have been >>>>moved to legacy support. NVIDIA nForce products will not be supported for Windows 8 and later >>>Windows operating systems.
Not a promising sign....