Is the configuration generated by nvidia-xconfig not used?

[TopCoder2K]

Does startx.py take into account a config generated by nvidia-xconfig?
It seems it doesn't since startx.py uses the following command:

Xorg -noreset +extension GLX +extension RANDR +extension RENDER -config %s :%s

So, Xorg uses a config generated by generate_xorg_conf(devices) not by nvidia-xconfig.

I also tried to start X-server with sudo Xorg -noreset +extension GLX +extension RANDR +extension RENDER -config /etc/X11/xorg.conf and the detected devices were better configured as far as I could see in the Xorg logs.

[TopCoder2K]

Also, I want to note that if starting with the config from nvidia-xconfig leads to some errors on your server:

[3096300.263] (EE) NVIDIA(GPU-1): UseDisplayDevice "None" is not supported with GRID
[3096300.263] (EE) NVIDIA(GPU-1):     displayless
[3096300.263] (EE) NVIDIA(GPU-1): Failed to select a display subsystem.
[3096300.519] (EE) NVIDIA(1): Failing initialization of X screen

which ends up with

[3096300.519] (EE) Screen(s) found, but none have a usable configuration.
[3096300.519] (EE)
Fatal server error:
[3096300.519] (EE) no screens found(EE)

try sudo nvidia-xconfig -a --virtual=1280x1024 instead of sudo nvidia-xconfig -a --use-display-device=None --virtual=1280x1024. For details, please see this.