Zero,
Since BIAB can only use one VSTi at one time, then RAM is not really a limiting factor. Furthermore, if you are running a 32 bit application like BIAB in a 64 bit environment, you still should have full use of all available RAM.

The interface has nothing to do with 32 bit or 64, and that discussion has been done to death over the years.

Finally, BIAB isn't really a sequencer. Real Band, yes, or even Power Tracks Pro Audio, but for those who are looking for 64 bit stuff, they'll be going to Sonar, or some of the others. By the way, I have Vista 64 Ultimate, and Sonar 7, and I can't use Sonar in 64 bit mode because of lack of driver support for 64 bit on my sound cards. That is the limitation there, so I'm running it in 32 bit.

Gary

I'm blessed watching God do what He does best. I've had a few rough years, and I'm still not back to where I want to be, but I'm on the way and things are looking far better now than what they were!