You can open it without data to do design modifications. If you need some data for design, you can then do a limited load uisng the debugger.
A downside of limited load is that you don't necessarily get linked records. An alternative is to keep a data reduced version of the dashboard around and use that version to do the design work. If you have Publisher, set up a reduce task that limits data to something like Region. Run that task when you need to make a fresh reduced copy from the master.
I would assume that your data model itself will not take that much of the memory.
What if you create a new qvw document and do a binary load of your original qvw? How much RAM will be used?
I assume that you are using some (or a lot of) chart objects with complex expressions. Could this be the case?
You can open your original qvw without any data (there is an option e.g. in Start page to open a recently opened document without data). Then copy your chart objects to the new qvw (the one with the binary load), one after the other and watch your RAM to identify the problematic chart.
Try to redesign your expressions, if possible (e.g. by creating flags in the script).
