In this particular example (Windows 10 with SSD drive with BitLocker enabled) reading 1 MB file is now 2.5 times faster, while writing is 5.5 times faster.
The memory allocations dropped from 39 kilobytes to 192 bytes! This is a 99.5% improvement! 

SQL Server 2019 (Windows vs Linux) and a Simple Test Scenario to Spot the Difference 

What is the difference between ToArray and ToList? 

Loop alignment in .NET
Performance and stability improvement 

Guest Jon P Smith shows how he built a demo e-commerce book selling site that uses EF Core. He started with 700 books then scaled through 100,000 books to ½ million books. At each stage he compares the performance of each improvement, and the extra work to get that performance. 

Five levels of performance tuning for an EF Core query 

The Growth of Web Page Size 

Entity Framework Core 5 – Pitfalls To Avoid and Ideas to Try 

Framework Benchmarks Round 20 - TechEmpower Blog

In this article, we’ll take a close look at some of the changes we made on this very site — running on JAMStack with React — to optimize the web performance and improve the Core Web Vitals metrics. With some of the mistakes we’ve made, and some of the unexpected changes that helped boost all the metrics across the board.