[drzaiusx11]

Great context, thanks! I knew it worked (I closely followed mono development at the time) but I didn't have a windows license/windows machines at the time it was ongoing to compare it to. 4x is pretty bad, any ideas what went wrong? Lack of jit maybe? I forget the exact architecture of mono at that time, being like 20 years ago...

[seabrookmx]

It did have a JIT, it just wasn't a very performant one. I recall the GC implementation also being quite slow. GC is an area where .NET is still making strides.. we got a new collector in .NET 10.