Does anyone know if there is a setting that enables all processor cores to be enabled for certain operations ?

Bethesda in their stupidity, decided to disable all cores, except 1 when you make textures for lod. See below -

Using 8 processors/cores.
Switching to singlethreaded mode since we are only building textures.
Creating queue of files to be built...
Building 256 chunks at level 4.
Building 64 chunks at level 8.
Building 16 chunks at level 16.
Building 4 chunks at level 32.
*** Building level 4 ***
Finished level 4 at (-32,-32) on thread 0; took 7.584000 seconds.
Finished level 4 at (-28,-32) on thread 0; took 7.529000 seconds.
Finished level 4 at (-32,-28) on thread 0; took 7.539000 seconds.
Finished level 4 at (-28,-28) on thread 0; took 7.533000 seconds.
Finished level 4 at (-24,-32) on thread 0; took 7.524000 seconds.
Finished level 4 at (-20,-32) on thread 0; took 7.545000 seconds.
Finished level 4 at (-24,-28) on thread 0; took 7.496000 seconds.
Finished level 4 at (-20,-28) on thread 0; took 7.493000 seconds.

I had to laugh at the 'only building textures' bit. It takes longer to build the texture than it takes to build the meshes. In the example above, it took ~1 minute to build 8 textures, as opposed to taking ~8 seconds, if all cores were utillised. On a 64x64 world, that's 340 textures and takes ~40 minutes instad of ~5.

If it was a 'do once' job, then that's fair enough, but on the project I'm working on, I'll find myself doing this quite a lot.

That's interesting...I'll have to follow this topic

In its present state, nope. While it's possible to override it manually (by patching the CK executable), there's a fair chance that it'd bring down the fort as the code used to generate the textures probably assumes that there is only gonna be one worker thread.

To be fair to Bethesda, I think the "only" part referred to doing a single, necessarily non-parallel process. I.e. "nothing but this single-thread task" If the process did many different things at the same time, it could run on multiple cores, but if the process can't, that comment seems reasonable.

However, that begs the question of whether it could have been written for parallel execution in the first place.

When generating meshes, 1 core is used for 1 mesh, so 8 cores are working on 8 different meshes at any one time, not 8 cores are working on 1 mesh at any one time.

I would have thought that the same logic could/should have been implemented for the textures.

Meshes are generally a 1 off. Once your landscape is sculpted and you're happy with it, that's it, you generate the mesh. Once they are in place, you'll never have to generate them again.

Textures/lod on the other hand, is an ongoing trial and error task, that's going to take 100s of hours for a large worldspace. This is the reason that i thought it was a stupid decision to disable/not implement it for texture/lod generation. I realise that they didn't use the CK for making the Tamriel worldspace/lod, but, by the way it's worded, it looks as though the code was in place and they disabled it because it's 'only building textures'.

Looks like I'm stuck with it if there is no setting to enable all cores.