Next 12 Build Performance on Windows

### What version of Next.js are you using? 12.0.2 and 12.0.3-canary.9 ### What version of Node.js are you using? v14.15.4 ### What browser are you using? Any ### What operating system are you using? Windows ### How are you deploying your application? N/A ### Describe the Bug Despite the announcement (https://nextjs.org/blog/next-12#faster-builds-and-fast-refresh-with-rust-compiler) the build time of Next12 app on Windows was not improved: - empty application created with `create-next-app@latest` - the build is the same comparing to `create-next-app@11` (approx. 7.8 seconds) - small-size application (5 pages, 2 API endpoints) - the build is ~50% slower after updating with `npm i next@latest` by 50% (22.4s vs 32.0) Upgrading to `next@canary` makes no difference. Others have reported similar or even worse results: https://www.tpjnorton.com/blog/posts/next-js-12-performance-test-builds-appear-to-be-slower-not-faster ### Expected Behavior Faster build with next12 comparing to next11. ### To Reproduce In Windows Powershell run: ``` npx create-next-app@latest cd app-name Measure-Command {npm run build} Measure-Command {npm run build} ``` Compare results with: ``` npx create-next-app@11 cd app-name Measure-Command {npm run build} Measure-Command {npm run build} ``` Both build commands (with cold and hot cache) execution times are +/- the same.