GTX 460 1GB + Quad Core + 8GB RAM - So why does Skyrim have lag spikes

Hi guys
I recently upgraded my graphics card (first a 6850 then settled on a GTX 460 because of Mass Effect 3 issues with 6850)

But I have a huge annoyance - Skyrim has lag spikes.

None of the fixes I found online have worked so far.

I have an AMD Phenom II X4 3.2Ghz
GeForce GTX 460 1GB 192bit version
8GB RAM

I feel like I should be able to play it on High settings without the lag.
It happens especially when I move the mouse around to look at the scenery (I play 3rd person)
But sometimes even when just running in straight line.

FPS drops suddenly, it's like a hiccup. Then it continues fine.

I tried it just for kicks on Low settings and it didn't have the problem, but I just can't believe high settings would cause such lag spikes, I feel like my system is pretty decent.

Anyone have some advice they know for sure it can help?
Maybe someone with a similar build can show me their ini's?
I'm going crazy editing the inis back and forth.