U r'nt increasing RAM, but adding SWAP as virtual memory. SWAP is memory management technique where OS is allocating data in block structures with same size - pages - for use in RAM. Inevitably, there is latency - from fastest to slowest - CPU registries, L cache, RAM, pages.
Think of SWAP as cache - a kind of a waiting room in ER. It's much faster to enter MD's office from waiting room than to come from home && enter when it's ur turn.
Regarding that particular app, I haven't experience - try it - but u can create SWAP from ADB shell if root privilege is accessible && busybox is present.
If u want to try creating SWAP from ADB shell, I suggest reading thread on this fourm about this topic, article on MIUI and XDA thread about init.d support. I was consulting that resources when making SWAP for ROM I made.
If u find u need more help, describe what ROM is used (everything else is already supposed), hence I'll make u a script with necessary files.