iMac 2019 Overheating with Catalina

Would like to if anyone have encounter the issue of overheating using iMac 2019 with Catalina. I have a machine running at 3.6Ghz i9, 64GB Ram with Radeon Pro Vega 48 8 GB. The machine will heat up even though I am not doing any rendering. The fan will kick in spinning loudly. Sometimes it will freeze or blackout. Not sure what is causing the problem but hope to seek some advice from the community.

Thanks