I am seeing 500~600k tasks/second in .NET6 w/ TPL.

Edit: Updating per request below.

Tested on a TR2950x. I wonder if NUMA issues in my case or bad python version (3.9.4).

Python

  100,000 tasks    77,108 tasks per/s
  200,000 tasks    69,945 tasks per/s
  300,000 tasks    72,453 tasks per/s
  400,000 tasks    74,636 tasks per/s
  500,000 tasks    66,253 tasks per/s
  600,000 tasks    77,576 tasks per/s
  700,000 tasks    69,673 tasks per/s
  800,000 tasks    68,176 tasks per/s
  900,000 tasks    73,846 tasks per/s
  1,000,000 tasks          68,013 tasks per/s

.NET 6

  100000 Tasks 523000 Tasks/s
  200000 Tasks 550000 Tasks/s
  300000 Tasks 550000 Tasks/s
  400000 Tasks 559000 Tasks/s
  500000 Tasks 547000 Tasks/s
  600000 Tasks 539000 Tasks/s
  700000 Tasks 547000 Tasks/s
  800000 Tasks 540000 Tasks/s
  900000 Tasks 560000 Tasks/s
  1000000 Tasks 542000 Tasks/s