Reasons why your ASP.NET server could be slow and how to improve its performance

Server performance issues might arise at any time and due to multiple reasons — memory problems, delayed database requests, shortage of machines are just a few examples.

In this post, we’ll learn about ten different types of faults that can wreak havoc on your server’s performance. Understanding them in detail may provide some inspiration and point you on the correct path the next time you’re looking into any performance difficulties.

Let’s quickly begin with the article.

Table of contents

  1. Reasons why ASP.NET server could be slow
  2. Tips to improve performance
  3. Conclusion

Reasons why your ASP.NET server could be slow

Here are some very common issues that could be pulling your ASP.NET server down and not letting you enjoy its full capabilities -

Slow Database Calls

There are certain issues that can cause sluggish database requests and degrade the speed of your application. Here are they -

  • Bad indexing strategy
  • Bad schema design
  • Work done on the server instead of on the database
  • The database is far away from the server
  • Inefficient queries are always a possibility

The most difficult part of tackling these issues is recognizing them in the first place. There are a variety of tools available to help you see how your requests perform in production. Typically, these tools will be able to show slow queries, scaling issues, network constraints, and so on. Application Insights is a classic example.

Memory pressure

Memory pressure is one of the biggest performance-related culprits in high-throughput servers. The garbage collector is usually unable to keep up with memory allocations and deallocations in such situations. When the garbage collector is overworked, your server spends more time collecting garbage and less time executing code.

This state can occur in a variety of circumstances. The most common scenario is when your memory capacity is depleted. Poor cache management or memory leaks are to be blamed for this. With a memory profiler, you can easily figure out what’s eating up all the memory.

Request hangs

Requests can hang in certain circumstances. To put it another way, you issue a request but never get a response. Alternatively, you’ll get a timeout answer. This can usually happen if the part of the program that handles the request is stuck in a stalemate. Or if you’re stranded in an infinite loop (referred to as a CPU-bound hang). Or if you’re waiting for something that never arrives, such as a queue message, a protracted database response, or a call to another service.

Server crashes

The application will not crash if a regular exception occurs during a request. The server responds with a 500 error code, and everything goes back to normal. However, if an exception occurs outside of a request context, such as in a thread you launched, a crash may occur. There are other fatal exceptions such as OutOfMemoryException, ExecutionEngineException, StackOverflowException, etc. All these will cause performance issues.

Tips to improve performance

Here are some strategies that can be used for improving performance in your ASP.NET server -

  • Use Kernel-mode cache. It is of the most extensively used technologies for developing speedier web applications. But, most of the time, we don’t use it to its full potential and miss out on significant advantages. We can implement caching at many levels as each ASP.NET request passes through various steps.
  • Use IIS. There are two pipeline modes accessible at the application pool level: classic and integrated. Many capabilities in IIS are implemented as modules, and many features in ASP.NET Pipeline are implemented as an HTTP Module. In classic mode, each request is processed via the IIS and then the ASP.NET pipelines before being served. Many functionalities, such as authentication, are shared by the two pipelines. In Integrated mode, these two pipelines are integrated into one, and all modules (IIS and ASP.NET) are triggered as they come along from a single event, reducing redundancy and improving application speed.
  • Reduce the number of customer requests, and you’ll be able to use fewer server machines or reduce the burden on the ones you already have. Here are a few ways to do it -
  • Modify synchronous calls to asynchronous calls. This is typically accomplished via a queue service such as Kafka or RabbitMQ (Azure has queue services as well). You would send a message to such a queue instead of sending a request and waiting for a response. These messages will be pulled and handled by the other service.


Many things can degrade your server’s performance, and there are numerous possibilities for mistakes to happen. Unfortunately, there are no shortcuts to developing a quick and reliable system if you think about it. You’ll need meticulous planning, competent engineers, and plenty of time to account for unexpected events. 90% of the work is usually spent detecting the problem and determining the root cause.

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