What's happening on project start?

Question

I've read several threads concerning this or similar problems and I'm still confused.
Basic observation is that everytime I launch PPro CS5 and start an existing project the last step is loading the file assets of that project in a process that takes an annoyingly long time to complete.  For example a project that has about 300 pure video files (m2v) and 20 audio files (wav) takes about 8 minutes to load these assets - each time I start the project anew.  Judging by the progress note in the lower left of the window, virtually all the time is spent on the m2v video files, not the audio.  I see no evidence of any video file conformation - the Preview File folder and Encoded Files folder are empty and the Media Cache has only audio files (.pek) in it.  What is going on that takes so long and why does it go on each time I reopen a project?
Particulars of my system:
       i7 930 2.8GHz QuadCore with hyperthreading
       12GB of memory
      Windows 7 64-bit
       NVIDIA Quadro FX 4800 display processor
       4 7200RPM 1TB drives with OS on one, cache folders on another, and project files on a third
No networked storage, no reloation of files or folders during projects.
All source files are brought into the projects through the import process.  A problem with large batch imports is discussed in an earlier thread, but otherwise the imports seem normal.  After an import a .pek file is created in the Media Cache folder for each audio file and a 4kB .xmp file is created in the same folder as the source files for each video file.
I thought that PPro added some xmp tracking data to the video files when it could and put this data in a separate .xmp file when it could not.  I also thought this was a way of tracking the source files so subsequent activity, like reopening the project, would not have to start from scratch each time.  The last mod dates on my source file have not been altered, so I assumed PPro could not get the xmp data into them and instead created the sidecar files. But my .xmp files seem to have no effect on subsequent source file loading.
Also I have no "project file bloating" per an earlier thread.
Do I just live with this annoyance or can something be done to reduce project loading times?

Answer 1

Jim - I did a check and the time to load all the selected clips onto the time line is not much longer than the time to read all the source files off disk.  So I guess its as simple as that.
The video clips are loaded on the timeline from last to first.  All audio clips are loaded at the end of the process.  Your answer implies that once the tail end video clips are loaded on the timeline and as long as the audio tracks are locked, I can begin further editing on those clips without interfering with the loading of the earlier files / clips.  Is that right?