Q&A
Improving Performance in .NET Applications
Every developer wants applications that run faster, allocate less memory and scale more smoothly under real-world pressure. But in .NET, as in any platform, performance rarely happens by accident. It comes from understanding what code is actually doing when it runs, knowing where the hot spots are, and using the right tools to separate assumptions from measurable evidence.
That is the focus of Improving Performance in .NET Applications, an intermediate-level session at Visual Studio Live! @ Microsoft HQ, taking place July 27-31, 2026, at Microsoft Headquarters in Redmond, Wash.
In the July 30 session, Jason Bock, C# MVP and Staff Software Engineer at Rocket Mortgage, will cover what .NET developers need to know to improve application performance, including how to address performance problems in code, spot bad patterns earlier and use .NET tools to find and fix slow code.
"It's not a good feeling to find hot spots in applications, but it's satisfying to come up with a solution that has faster results and/or fewer memory allocations."
Jason Bock, Staff Software Engineer, Rocket Mortgage
The topic lands at a moment when .NET development continues to evolve well beyond the old .NET Framework era. Modern .NET is cross-platform, open source and the center of ongoing platform investment, whether developers are building web applications, distributed systems, AI-adjacent services such as MCP servers, or other applications that need to run efficiently across environments. With each release, the runtime and libraries continue to add performance improvements, but taking advantage of them still requires developers to understand the tradeoffs in their own code.
For Jason, that means looking not only at obvious slowdowns, but also at memory allocations, framework choices, migration decisions and the configuration practices that help teams catch issues earlier. His session is set to emphasize practical diagnosis: how to find the parts of an application that are really causing trouble, how to evaluate potential fixes, and how to use modern .NET features and tools without treating performance as an afterthought.
One example is Span<T>, which Jason identifies as a major influence on modern .NET performance. Even developers who do not use it directly can benefit from the way the runtime and APIs have increasingly adopted it to reduce memory consumption and speed up implementations. That kind of platform-level progress can make a real difference, but only when developers know where it applies and how to recognize opportunities in their own applications.
Ahead of the session, we asked Jason what inspired the talk, how developers should think about modern .NET applications, what teams often get wrong when modernizing legacy apps, and why performance work remains one of the most satisfying -- and ongoing -- parts of software development.
VisualStudioMagazine: What Inspired You to Present on This Topic?
Jason: I've always had an interest in improving the performance of code that I've written. It's not a good feeling to find hot spots in applications, but it's satisfying to come up with a solution that has faster results and/or fewer memory allocations. I also like teaching and helping others, so whenever I can I give tips or learn from others on what they've done to make performance better.
What Key Characteristic Defines a Modern .NET Application Today?
You're no longer using .NET Framework. Seriously! While someone can build a good application in .NET Framework, it's clear that there is no future with that version of .NET. .NET is where all the new work is taking place, it's cross-platform, and it's open source. It's the train you want to be on for modern application development in .NET, whether that's building MCP servers, writing web applications, or really wherever your code needs to run.
How Do You Balance Rapid Development with Long-Term Maintainability?
That's always been a struggle, and it's amplified even more with the rise of LLMs. I've always tried to find ways to configure codebases in such a way that suggestions and warnings come through loud and clear. That way, you have a better chance of writing code that will have fewer issues overall. While it's not a panacea, it generally makes it easier to maintain applications over their lifetime.
What Is a Common Mistake Teams Make When Modernizing Legacy .NET Apps?
Underestimating the effort! Even with agents in Copilot that can assist with the migration, there can be a whole host of dark corners within an application that can be very difficult to determine how to move from .NET Framework to .NET. Use tools wisely and come up with plans that clearly identify simplistic effort and potentially problematic areas. Finally, be open to the fact that the right answer may be to just rewrite it from scratch -- modern tooling helps in easing this work.
What Tool or Feature Has Had the Biggest Recent Impact on .NET Development?
The Span<T> type. It's just one type, but its impact has been substantial in improving the performance of .NET code. Even if a developer doesn't use it directly (and they should always be on the lookout to see if they can with newer APIs), the runtime has evolved to using Span<T> in more places to drastically reduce memory consumption and speed up member implementations.
How Can Attendees Learn More About This Topic, and Prepare for Your Session?
There's so much to study when it comes to application performance -- it's arguably a topic that you can always learn something new about. If there's one source to start with, I'd suggest the .NET performance articles that Stephen Toub, a Partner Software Engineer at Microsoft, writes with every release. The latest one for .NET 10 is here. He's done this with every .NET version since .NET Core 2.0, and they're dense with technical information on how .NET gets better with each release. I've found them to be highly educational, and I look forward to reading the next one when .NET 11 is close to release.
Note: Those wishing to attend the session can save money by registering early, according to the event's pricing page. "Save $300 by registering by the June 19 Early Bird Savings deadline!" said the organizer of the event, which is presented by the parent company of Visual Studio Magazine.
About the Author
David Ramel is an editor and writer at Converge 360.