I marked the thread as [WIP], but it actually is or was more of a proof-of-concept where I would like to share the results with you. I recently came across the following feedback item: https://feedback.unity3d.com/suggestions/vector3-and-other-structs-optimization-of-operators It says if Unity would not use custom constructors in their code, such as the Vector3 math implementation, the program execution could be a lot faster. He made a test by implementing an own set of Vector math and improved performance a lot. I thought it would be interesting to find out how it affects performance, if these changes would actually exist in Unity's own dll files. In other words, like if Unity Technologies would make these changes to Unity. In this case, nobody would have to change any code in their project and simply every Unity game might run automagically faster. Too good to be true? Let's find out! I wrote a tool which I call "IL Optimizer", that replaces code in Unity's DLL. For example, ILOptimizer replaces many Vector3 method implementations to avoid calling custom constructors and even inline's some method calls as well. The performance improvement is actually impressive. My game runs about 4% faster. That's a lot for simply not doing any changes in user code and just replacing some trivial code in the UnityEngine.Vector3 class. I did another Vector3 non-sense test, where I process 128*1024 Vector3's and do some math on them. While I believe only a few project have such heavy Vector processing, it also improved performance a lot. The performance improved from 34ms down to 25ms. It runs 11ms faster, that's like 30%?!, simply by replacing a few Vector3 methods! Here is a video where I explain what the tool is doing. A message to Unity Technologies: You can make every project on this planet that uses Unity run significantly faster with a few trivial changes in your Vector classes. Also, why is Vector3Int using properties rather than fields for its members?