R-Mix Issues; anyone else?

Hello,

Is anyone else experiencing issues with R-MIX?

I'm running a pretty beefy system: i7/12GB Ram/Win 7 64-bit with a RME UFX interface.  

I recently tried to use R-Mix on a relatively large project (53 Tracks with 15+ VSTs).  I inserted R-Mix on a "catch-all" bus.  The R-Mix interface couldn't even show a visual on the signal coming in.  I closed down the project and reloaded.  I then got a signal but the sound was intermittent.  As though R-Mix was only able to capture part of the data coming in.

A few day's later I tried it on a project which consisted of just one track which was a mix down of another project.  That worked just fine.

So I was wondering if there are bandwidth limitations with R-Mix, has anyone come to learn what the functional parameters are?  It would be nice to know what are the limitations.  I was actually counting on using it on the large project but now it seems I will have to use it on the mix down track rather than in the project itself. 

Also, upon setting up all of the automation and saving then closing the project, upon reloading the project, I had to re-select the effect I was using before even though the effect that I had previously selected was still shown in the selection window.