Why is ASP.NET Core faster than ASP.NET? – An Interview Question That Taught Me Something Valuable

Ravi Patil — Thu, 24 Jul 2025 04:59:42 +0000

In a recent interview, I confidently said:
“ASP.NET Core is faster than ASP.NET.”

The interviewer immediately followed up with:
“That’s good to know. But how exactly is it faster? What improvements make it perform better?”

And to be honest — I didn’t have a solid answer at that moment, I knew some of it like it's lightweight and platform independent but after that I was blank.

That question stuck with me. So, after an interview, I decided to dig deep and find out what really makes ASP.NET Core stand out in terms of performance.

🚀 7 Key Reasons Why ASP.NET Core Outperforms ASP.NET (Full Framework):

1️⃣ Kestrel Web Server
ASP.NET Core uses Kestrel, a fast, cross-platform, lightweight web server designed for high-performance scenarios. Unlike IIS in ASP.NET, Kestrel handles requests more efficiently with less overhead.

Now search about the Kestrel server and get to know how it is faster than IIS and what goes under hood.

2️⃣ Asynchronous by Default
ASP.NET Core promotes async/await throughout the framework. It handles I/O operations without blocking threads, which improves scalability and responsiveness under high traffic.

3️⃣ Modular and Lightweight
You only include the necessary libraries using NuGet. This results in a smaller app footprint, faster startup, and better memory usage compared to the monolithic ASP.NET model.

4️⃣ Improved Garbage Collection
ASP.NET Core includes optimized GC, Server GC by default, and support for Span and Memory to reduce memory allocations and improve runtime efficiency.

5️⃣ Cross-Platform and Cloud-Ready
ASP.NET Core is designed for containers and runs on Linux, macOS, and Windows. It works smoothly with Docker and scales well in cloud environments.

6️⃣ RyuJIT Compiler
ASP.NET Core uses the RyuJIT compiler, which produces better-optimized machine code, supports SIMD, and compiles code faster with lower CPU usage.

Search about RyuJIT Compiler and you will be amazed by it.

7️⃣ Minimal APIs and Razor Pages
For modern web apps and APIs, ASP.NET Core supports lightweight patterns like Minimal APIs that cut down routing and middleware overhead.

💡 What I Learned
Sometimes, it's okay to not have all the answers during an interview. What matters more is the curiosity to go back, research, and truly understand the "why" behind our everyday tools.

This question helped me grow, and now I’ll never forget the reasons behind ASP.NET Core’s performance advantage.

Has anyone asked you a question in an interview that led to a deeper learning afterward?
Or have you noticed real performance differences between ASP.NET and ASP.NET Core in your projects?

Let’s share experiences in the comments!

Forem: Ravi Patil

Why is ASP.NET Core faster than ASP.NET? – An Interview Question That Taught Me Something Valuable