In addition to having more control over CPU/GPU/RAM usage, another reason for introducing the manual CPU core allocation setting in 2.0.5 was to get some additional feedback regarding a pesky import bug that has been affecting a few users. Observatory appeared to be leaking an enormous amount of memory during importing for them, or create many threads. This could lead to a crash or even require a complete reboot. Sometimes the import would stall without the user interface actually being frozen.
Both issues were caused by the same bug. It has been fixed in Observatory 2.0.6.