you are getting low fps and gpu usage is on 45% because the skyrim uses cpu more then gpu it is badly optimized well if you overclock your cpu you will get more performance in skyrim and other cpu dependent games.for example if you will play bf3 there will be an smooth gameplay because it uses both cpu and gpu thats why.
Skyrim is completely CPU-bound and optimized like crap. It's better than at launch, but still bad. With any $200+ graphics card in Skyrim, your minimum framerates are determined pretty much entirely by your CPU.
If you want to see higher GPU usage, you need to mod the hell out of it - and that won't increase performance, just the amount of workload given to the GPU.
You'll also find that RPG's tend to be a lot more CPU bound than GPU bound. When ever you go into towns full of NPC's, the CPU has a lot more to work figuring out the AI and physics. The same thing happens in FPS games when you have a bunch of enemy around you, but it happens far less, because FPS games almost never have that many NPC's lumped together.
RPG's generally have more CPU load than FPS. It's not a matter of being lazy, it is just the nature of the genre. That said, out of the box, Skyrim only used two cores, which hurt performance a lot. Now that it uses more, after some patches, it's quite reasonable.
*It seems very possible to drop to 45FPS if you have maxed out the settings. My advice is to adjust Anti-Aliasing and other settings so that you achieve 60FPS with VSYNC enabled most of the time. A small drop in quality is worth it to avoid screen tearing (VSYNC disabled) or major stutter (VSYNC enabled but dropping below 60FPS).