Why are calculations so slow?

Question

Video cards

The video shows the result of a simple C# program
https://youtu.be/LoNxNFkYFoc
Why is the calculation of this code so slow? How to achieve a result of at least 1,000,000 per second. Processor i7-8700
Perhaps you can use the power of the video card to speed up? If yes, how to do it?

Answer 1

Slow not calculations and an output in the console. Just remove the output to the console and add it to the end. Why use vidyuhu for this?
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Answer 2

Console output on Windows stops execution