The nvidia-410 is a driver, but Xorg is still there. nvidia-410 in no way replaces Xorg…instead it plugs into Xorg as a dynamic module (a supplement). The thing to understand about the binary video drivers is that they are bound to a specific ABI release number of Xorg. So long as the driver is matching the correct Xorg release it should work. The drivers are not normally able to accomplish anything outside of Xorg (at least for most purposes).
The 100% CPU with Xorg is not necessarily related to the driver (if you just mean that CPU is working at full capacity…it is a different story if you mean that GPU is not working). Xorg can run a window manager, and many applications can be dependent upon this. If you are saying GPU is not being utilized, then it sounds like mesa has replaced the NVIDIA driver. Mesa is both a set of tools and a driver…NVIDIA replaces only the driver portion. Neither mesa nor NVIDIA replace Xorg.
If you install package “mesa-utils” (“sudo apt-get install mesa-utils”) you should get the program “glxinfo”. Then run this command to see which version of driver you are using for direct rendering (must be run inside of an X session):
glxinfo | egrep -i '(version|nvidia)'
If it is mesa, then this will also show a failed file (because of libglx):
sha1sum -c /etc/nv_tegra_release
Assuming the driver shows NVIDIA, and not mesa, then your install worked. You won’t have the nv_tegra_release file on a PC, but the glxinfo command would be valid on both PC and Xavier.
Btw, the mainstream PC drivers have a name such as “nvidia-410”, but all PC drivers assume PCI. The GPU of an Xavier is directly wired to the memory controller and there is no such thing as a driver for the PC which works on the Xavier…this would be true even if Xavier was the same architecture of CPU (which it is not).
Without knowing more about what it is that causes the CPU to be pegged at 100% there isn’t much that can be said. On the other hand, if instead you meant that only CPU is being used, and no GPU is being used, realize that the default in Xavier is to have GPU used…mesa is not normally the driver unless something went wrong. The “sha1sum -c /etc/nv_tegra_release” is in fact checking files related to hardware drivers to see if any were overwritten by something unaware of NVIDIA hardware. GPU itself won’t be utilized unless the program you are looking at was written to use the GPU…GPU use is not automatic.