Windows 7 Performance Disk Data Transfer Rate

I have a Dell XPS 8000 with a quad core, 8 gig ram, 7 pro, 6gb hdd and 6gb controller. I've tried SSD's that were 6gb and still having issues with slow performance. My main program is Arcview Mapping. I"ve tweaked the cache, I've put the Win swapfile on a second 6gb drive, tried 'no swapfile' so it all runs in ram, just about everything I can think of. We have gigabit nic, switch to switch, etc. It uses a lot of updates to the screen straight from internet, but local files should load faster. I have a copy on my local 6gb drive then sync to server at eod trying to r/o net latency. Majority of work is to/from local drive, but still can't wring out more speed. When I open Arcview, it takes 1.5 minutes to get to a workable screen. File size I'm loading doesn't make a diff.