This might be the cause of your problems. To convey an impression : having worked with dt for about half an hour, htop shows the following usage of memory (only dt !) :
RES (physical memory) 1.613 GB
SHR (shared memory) 172 MB
VIR (virtual memory) 13.3 GB
And I have some experience working with a nine year old system with only 4 GB of ram where I observe crashes from time to time which I have never seen on a new system equipped with 64 GB of ram.