GTX 780 Ti - CUDA selected, but GPU isn't doing anything

Question

I know there's a bunch of posts on the 780 Ti, but I've been researching for days and I'm getting nowhere.
Disclaimer: First let me just quickly say this. I know it's not officially supported and I understand why, so please don't mention that. I'm a long time PC enthusiast and builder and I've worked in technical IT positions for 15 years. I understand liability implications of testing hardware and officially supporting something, and also the implications of using unsupported configurations (like PP maybe randomly crashing, etc). Now, with that said:
The Issue: In PP CC 2014, CUDA is available and it is selected. In fact I never had to select it. It has always been automatically selected when creating new projects. However, my cards aren't doing anything. They're idle 100% of the time.
I've read posts from users and from Adobe stating that unsupported CUDA capable cards will still work as long as the user accepts a message stating that the card isn't supported. However, I don't ever recall getting a message saying anything about my cards being unsupported. I only know about said message because it's been mentioned by Adobe and other users. I'll admit that I may have, in fact, been prompted and clicked accept, or continue, or whatever, but I'm pretty sure I would remember that. I also wouldn't have been surprised to see the 780 Ti missing from the supported cards list, which I only went looking for after learning that it wasn't using my cards.
I've messed with PP settings, NVIDIA settings, uninstalled/reinstalled drivers, older drivers, beta drivers, uninstall/reinstall PP CC 2014. I read something about deleting the CUDA file so I tried that but I think that's not supposed to be necessary anymore(?)... I'm losing my mind here.
1. I've read that exporting media "only uses the CPU and not the GPU" and I've also read "CUDA GPU acceleration will significantly reduce export times". What's the official answer on this?
2. During sped up playback and reverse playback (normal playback is fine), the CPU is pegged and the GPUs are idle. Shouldn't at least this use the GPUs?
3. I've read that not all effects will or can use CUDA. For example when applying the warp stabilizer to clips, the CPU is pegged and the GPUs are idle. Does that not use CUDA? That seems like a pretty common effect that should be able to use GPUs.
I would really appreciate an official answer as to whether the 780 Ti will work or not - completely ignoring whether it's officially supported. If the answer is "yes, it will (should) work, but something is wrong with your particular setup/configuration" I'm ok with that, but I'm hoping there's a suggestion I haven't found yet, that might help get my cards working.
Thank you very much for any input you can provide.

Answer 1

See the thing is, I've already read that post a dozen times. It seems to be
the de facto response to all these "CUDA isn't working" questions, haha. I
know what CUDA is and how it works. My issue with that page is that it's
four years old, and the only two updates aren't dated and they're vague.
The CUDA capable effects list on that page is just outdated. I've also gone
down several rabbit holes of links starting on that page, which end on
broken links or non-CUDA-related content.
With all that said, that page does specifically mention cropping, scaling,
and exporting as GPU accelerated. In my example, I'm using the warp
stabilizer set to smooth motion - position, scale, rotation, and I'm not
using any crazy export settings, just defaults with 2-pass selected instead
of 1-pass for example.