Re: Xorg hangs at "Loading extension NV-GLX"
Sorry, I had missed that you appended the 2nd X log to the end of the bug report. In the 2nd X log, I see several WAIT messages, which can be triggered when the nvidia driver is mpt receiving interrupts from the graphics card. This could be a driver bug, or it could be a bug elsewhere (X server, kernel, BIOS, etc).
Please retest with 100.14.09, and if the problem persists, please verify:
0) That you're using the latest motherboard BIOS
1) Whether the problem persists if you run one X server for both GPUs