Having more than 2 cores makes virtually no difference in any benchmark and the game can't access more than 2 GB of RAM by default. Raw CPU clock speed seems to matter way more than a decent GPU, dual GPUs, or multithreaded & multicore CPUs. The engine still seems to be coded for 2007 era PC hardware, the consoles got all the optimization and you can't really blame them for that, but it would have been nice if they had given the PC some real love for a change.
It's still totally playable and looks great, but compared to other highly optimized multiplatform games and console ports, Skyrim just doesn't stack up in terms of performance and taking full advantage of the advances in PC technology and hardware improvements in the last 5 years. Most multiplatform games are still designed with the 6+ year old console hardware in mind, but usually on a modern PC with decent developer optimization that means the same games will absolutely fly at much higher resolutions and details because the modern PC hardware is so far beyond the aging consoles at this point. With Skyrim it's like everyone's machine from the mid end to the top of the line has been severely downgraded.
And the worst of it all is that the hardware utilization and optimization is never going to be overhauled or upgraded or improved to the extent we'd all want with an update if Oblivion and Fallout 3 are any indication. Aside from some minor performance tweaks that may or may not be implemented in the future, what you see now is what you'll get always (until maybe someone creates a dual core CPU fast enough to brute force everything?). They've already done the significant work on bundling their old tech into a new wrapper dubbed the Creation Engine, it's unfortunate that the current PCs got the shaft in the process.