Extremely high memory usage with deep scan

I started a deep scan (all files in a specific folder) and left. When I came back, my PC was very unresponsive. Turns out it was paging like crazy, because Recuva was using 3.6 GB of RAM (I have 4 GB of RAM and I was using almost 3 GB before I ran Recuva). Recuva was showing "100% done". Here's a screenshot of Process Explorer of Recuva's process just before I killed it:

recuva.png

Windows 7 x64 Ultimate

Intel Core 2 Duo E6600

4 GB DDR2 RAM

250 GB HDD