I have really big dashboard (~26GB in memory) When I load it in IE-plugin first time it returns and error:
qvp://<document path> could not be opened.
After this I can click Refresh the page and the Document works just fine. It means that the document is keep loading on a server while client session has been interrupted by some timeout. There is no such problem with Ajax client. Initial loading time is about 5 mins.
One thing you might want to look at is setting the document to preload in memory when the QVS Service starts. (This can be found under Documents > User Documents > Doc Name > Server Settings). Should open up faster this way.