Why does Space Marine 2 crash to desktop during large-scale battles?

Facing swarms of Tyranids, my 8GB RAM hit 97% usage and the game crashed to desktop, leaving me extremely anxious about stability. I tried setting all graphics to the lowest settings; while FPS improved, the game still crashed every 15 minutes. I used the GamePP Resource Scheduler to fix virtual memory at 12GB and set the game process priority to High. AIDA64 showed read/write latency stabilized at 78-82ns, and HWiNFO64 confirmed temperatures at 44-50℃ while memory usage stayed under 97% per HWiNFO64.