The aim of this study was to compare the performance of two Microsoft .NET (Core) product versions. Previous version upgrades to .NET (Core) had seen performance improvements over their preceding version. The need for performance assessment arose from software company RockOn’s software project, during which a new version of the used .NET (Core) product was released. It was argued should the project switch to use the newer software version.

The main task was to gather performance data of the company’s used software platform with the then current version and with the upgraded and version. To accomplish the task, quantitative research method was used to gather performance data of the software using two different software testing tools. Software tests were divided in to two separate sections. Practical web API performance was tested with load testing tool on the company’s produced software application. Non-practical code level tests were done on a separate software application.

The load test result for the application web API performance saw 160 % speed reduction for the new software version due to software application irregularities. The code level performance saw increase for the new version from 0,76% to 94,63%.

By analyzing the results it was concluded that the new .NET version had performance benefits over the older .NET version. The application anomalies and inconsistent load test data lead to deem the load test results as unreliable while the code level test results proved to be in line with findings by other data and as such were regarded as reliable.