Update after lot of testing.
On my RTX 3090/AMD 5950x, it seems I regained the FPS I lost with patch 1.6 by using new NVIDIA Drivers: +/-10fps drops with 1.6/1.61, +/-10fps gains with NV 526.61.
However, this is not surprising as DX12 has been improved with the new line of NV drivers... I mean...