PC restarts automatically

[refhat21]

Recently I upgraded my PC from MSI gaming trio 2080 ti to Asus strix 3090. First two weeks I only had coil whine issue during starting any newer gpu intensive games but after 30 seconds later the noise would go down a lot. From last week my pc restarting automatically during MSFS and call of duty cold war, first it was one or two times a day but now it’s happening 3 to 5 times, my power consumption monitor shows my system’s power never exceeded more than my power supply max wattage capability. Yesterday I put back my old 2080 ti back in the system and never had a system restarts. Can someone please tell me what might be the problem. My system- I9 9900K @5ghz Corsair vengeance lpx 3200mhz 32 gb, Asus strix RTX 3090 , Samsung 970 pro m.2 nvme 1 tb and Seasonic PRIME 850W 80+Titanium

[pederl]

Hi. I came here for same problem and solution. allso got Seasonic PRIME 850W 80+Titanium.

What i have read. The psu is the problem thou 850w should be just fine. Any luck without buying new psu?