Hitfilm Express doesnt use GPU

Hitfilm Express DOES use the GPU but you don't understand the render pipe and order of operations - and neither @triforcefx or @Stargazer54 made this explicitly clear.

Both mentioned that the CPU handles frame encoding and decoding, while the GPU handles VFX and frame renders. What they didn't point out is this happens in a SERIAL manner not PARALLEL. When the CPU is doing its tasks the GPU is idle and vice/versa.

Your figure of "70% CPU load and 20%GPU load" indicates Hitfilm is spending most of its time dealing with file I/O and relatively little time on rendering.

But, your headline statement of "Hitfilm isn't using my GPU" is objectively wrong. It's using your GPU, but knowing of that handoff between CPU/GPU will hopefully keep you from stressing out over Task Manager reports that don't really mean much. (I'm reminded of the occasional user we get who feels that CPU and GPU should always be pegged at 100%. Those are people who don't understand how computers actually work.)

You are using the Pan/Crop EFFECT. I suspect this is more resource intensive than the old/classic method of keyframing Scale and Position, although I never have done an A/B test for that.

Still, your task manager report might hint at that. Depends on if the FXhome "Render Client" is literally rendering frames or if it's managing the processes that render frames, I guess (Mods and Ambassadors aren't FXhome staff, certainly not Hitfilm devs, and have very little knowledge of how the software works beyond public statements made by devs).

When "the logo changed" (Hitfilm v16) Hitfilm shifted from an OpenGL 2.1 core to OpenGL 4.2 and from OpenCL 1.0 to 1.2. There was also a raise in minimum specs, basically from 2013 tech to 2016 tech. One can assume these versions of Hitfilm use more resources than older versions. This is typical in the tech industry (it's well known for example older iProduct gets slower when updating iOS or that a Windows box built for, say, Win 7 suddenly "got slower" if updated to Windows 10. Basically your machine is getting older and software is requiring more power). This has been a Hitfilm cycle for a long time - some change to the code core raises minimum specs, then the software feels slower on identical hardware, but each revision gets faster again until the next time specs go up. Actually, that's pretty typical of all my software.

Hitfilm EXPRESS v16 also shifted to use the native encoders/decoders in the computer's OS while Hitfilm PRO uses licensed third party libraries. There have been some issues that arose from this that didn't come up in Beta Testing (for example, Stargazer, Triforce and I are beta testers and we didn't encounter any of the now known bugs ourselves. Don't even THINK of saying "well they should have tested for everything," because there are literally tens of thousands of possible hardware configurations that can run Hitfilm only in the last two generations. It is literally impossible for any tech company to test their product on all hardware, and anyone saying they should merely betrays naive ignorance.). It's possible this might also have something to do with perceived slowdown. Certainly had something to do with the pixelation issues affecting some users.

Finally, Hitfilm has never been the fastest at plain old frame buffering. It is slower than most of its competitors at the "basic" task of pulling frames from the drive and writing them to the drive. In that case, it is what it is. I suspect it's due to the OpenGL render core. The devs have never confirmed or denied (and always ignore this when I speculate), but I believe all image/video objects in Hitfilm are actually texture mapped polygons. This would have advantages when setting up 3D workspaces and make it easier to have 3D models/planes/particles occlude correctly, but it does add an additional processor load just getting a straight video frame on the Timeline. It would also explain why anti aliasing in Hitfilm exports is global.

Anyways, again, Mods/Ambassadors aren't Staff/HF devs, so there's really nothing else we can do at this point other than refer you to support, which Stargazer already has.

The dev teams really do work quite hard.