Help with computer setup and PP settings for faster/better previews

Question

I have been using Cyberlink PowerDirector software for video editing.  It is very easy to use and can do quite a bit.  It was also accelerated by Intel HD graphics built into my system, so I could see a lot of my work at a pretty high resolution in real time.
However, I wanted to see what PP was capable of, specifically the Warp Stabilizer.
So I downloaded PP and have been trying to use it, but it was just slow as heck to preview anything (chop stop chop stop...), with render times being insanely long (12 hours for five minutes of footage vs. about 30 minutes with PowerDirector).
Thinking it was a problem with my system and I needed to get a real graphics card, I got an EVGA GTX 670 (FTW) for $400, and popped it in.  I modified the text file so PP would see it as a compatible card, opened up PP and changed the engine to the new card. 
Things are faster, but I was expecting a lot more.  Here's what I'm doing:
1. Shooting Canon 5D mark II (now III) clips 20-60 seconds long, 1080p.
2. Import to PP and sequence them.
3. Adding effects:
     A. Top adjustment layer for fast color correction (white balance)
     B. Next adjustment layer: 3-way color, shadow/highlight, unsharp mask, fast blur
     C. Video 1 layer has the clips with warp stabilizer applied to each, and dissolves.
My final output will be 720p.  ( I shoot 1080p so the Warp Stabilizer will have more to work with, and I can crop without feeling like I'm degrading quality).
My system: i7 2600k, 16GB RAM, GTX 670 graphics, 120GB SSD "Max IOPS", 2TB 7200rpm internal, 2TB 7200rpm external (USB 2.0, backup drive).
I can currently preview at 1/4 res in realtime.  I would really like to be able to get to 1/2 res (of course full would be great).  One thing that worries me is that GPU-Z indicates that my GPU is only running at about 2% while previewing, while CPU usage is at around 50%.  I was under the impression that the Mercury thing would use GPU/CUDA to process previews and effects that are supported (that includes Warp Stabilizer).
I've looked at Sequence Settings and fiddled with Preview File Format and size, but that doesn't seem to do anything.  I'm currently looking around at codecs (Cineform, DNxHD), but don't know if those can help.
What settings should I alter to get better previews? 

Answer 1

Well I'm still pretty clueless about this, but for anyone who is looking at this and wondering, here's what I've gleaned:
1.  After Effects, especially CS6, makes much more and better use of graphics cards than does Premiere Pro.  I'm guessing that PP will, in future versions, make better use of them.  For now, no need to spend more than a couple hundred bucks on one.
2.  Update the software.  PP and AE both performed substantially better after installing the .01 update from adobe.  After you install the update, be sure to re-do the CUDA hack, if necessary.
3.  As it stands, money for a PP system is best spent on a processor, as in the newest Intel (currently Ivy Bridge), and overclocked.  This is where performance happens.  I'd say on a 2012 system, 16 GB RAM should be considered a minimum for video editing, and 24 or 32 if you can afford it.  More than that probably won't be utilized.  Hard disks can affect performance, but I don't think it's a bottleneck unless you're doing something that requires VERY fast/large reads and writes (4k source?).  Most people who have high-end editing stations also have a bunch of drives in RAID, but if you look at the performance chart, the SECOND highest scoring tester did not use RAID (though did use a presumably fast and large SSD).
Keep in mind that all of this has to do with RENDER speeds.  I still don't know what the bottleneck is for PREVIEWS, but I'm just going to assume it's the same.