Well, you certainly are in range of what I'd say would be a good setup, but perhaps we're both missing some key item(s) that kick the speed up ...

Some links to check out

Powerful Photo/Video Editing at a Budget

Build a Monster Computer for Video Editing and Post Production

The Genesis II They want to sell you a dedicated workstation, but perhaps some "pre sales" inquiries would let you garner info to build your own.

This article is about a guy who wanted a pc for editing and has put together this video and list of hardware: Building Your First Computer for Video Editing ... he then has a newer version of the build with some adjustments after getting feedback from the first article.

Hope those help