using PhoenixMiner_5.5c_Windows and have slowdown with newer Nvidia drivers

nvidia v460.89 ~60 Mh/s
any newer nvidia driver (e.g. 461.40)  ~50 Mh/s
I've tried running PhoenixMiner as Admin - still ~50 MH/s
reinstall nvidia v460.89 back to ~60 Mh/s

Any solutions for reclaiming hash rate with newer nvidia drivers?  Many thanks.

Hash rate quoted while only running miner, with PC at lock screen.

Card:
Nvidia 3060ti
-500 clock
+1050 ram
60% power

PC:
5900X CPU
x570 MB
windows 10 64bit