And if you do know this already, good on you. I had been struggling with this issue for about a year, but today thought I would search newly for a solution. Turns out it's not really an issue after all.

For those of you who don't know this, this might come as a relief, or a shock that it was so obvious.

Without further ado....

I have discovered that while it appeared that my GPU was being barely utilized during a GPU render, with percentages in the task manager under 5%, it was actually the CUDA cores that were being utilized and were indeed almost 100% utilized.

There is a drop down in the GPU, 3D section of the task manager. Select CUDA and voila, you can see how much your render is actually using. Hope this helps clear up some confusion for people in the 3D Rendering Universe.

Cheers,

Tako Yakida