When you store a qvw, the default setting is a high compression format.
When you actually open it, it will consume more RAM.
If you perform a reload during the day, when the users are using the applications it will also consume more memory.
As a rule of the thumb, you can consider that after the first user accessing a document, each additional user may consume 10 - 15% more RAM.
If you are able to install QV Desktop on the server, you can open the files one by one to check (more or less) which one requires more RAM.
Hope this helps,
It turns out that the reason QVS was using so much memory was because of the Performance settings in QEMC. The machine has 32GB of RAM, and the memory limits were set to 70% - 90%.
After reading up on this, it looks like QVS will try to grab as much memory as it can until it reaches the lower limit. Then, it will grab more memory as necessary until it reaches its upper limit. When it reaches its upper limit, it will start resuing memory from its cache.