Looks like filesystem cache is never (or rarely) flushed when RAM is 1+Gb

I am always installing ReactOS with 1,5 Gb RAM, because otherwise it crashes too much. This seemed fine, while memory manager eats all ram on many big file operations, so system with 1+ Gb works much better. But... see the title.
If I had any BSOD my data become TOTALLY LOST, like Time Machine effect - all changes are like never happened before. No installed apps, no files, nothing. Like I didn't touched the system at all.
My clue is that fs driver thinks there is plenty of RAM so no buffer flush needed for a long time (probably eats all ram and then flushes... or BSOD happens and goodbye my data).