Task Manager - Page file

I am monitoring the crash of the system which appears to be caused by
the system running out of virtual memory. This is, at least what I see
in the Task Manager: the size of page file raises steadily as the
application caches new incoming data eventually reaching 100% and
causing the application to stop responding and finally terminate. This
is what I see in the Performance tab of the task Manager.

However, in the memory usage column for the application as shown in
the Processes tab of the Task Manager the reported number is not out
of ordinary. It is growing, as I would expect, but the number is well
below the amount of physical RAM I have on the system - some 30% of
the total or so.

How do I interpret this observation. What do these two numbers really
mean, the memory in the Processes tab and the page file size (ie. the
memory gauge in Performance tab).