VB6 is not OO. It does have some OO features, as you kind of mentioned (though modules are not OO, and don't really exist as such in .NET, since modules in .NET are quietly converted into classes with all shared members...plus some compiler sugar to hide the fact). The term OO used to have a strict definition, but it became "cool", and so it was stuck onto any program or language that had anything it could call an object. In strictest OO, you have nothing but objects (even C++ was not quite clean in this regard, but .NET is).

On the other hand, you mention polymorphism, encapsulation, and inheritance. I didn't remember any of that when I was writing in VB6, so I went looking for it. Here is an interesting link from MS:

https://msdn.microsoft.com/en-us/lib...(v=vs.90).aspx

Note the last line, which states:

Visual Basic 6.0 does not support implementation inheritance.
Here's another one from MS:

https://msdn.microsoft.com/en-us/lib...(v=VS.60).aspx

So, MS disagrees with you about their language, so what are you talking about?

As for speed, you said that VB6 is a lot faster, and now you are saying that you don't see a difference at runtime other than some time taken to load something. I can't say that I have seen any difference in launch speed for programs, either, but then again, not only have I never had an apples to apples comparison of load speeds in any of the programs I have written in both languages, I don't believe I ever saw such a comparison in the links I found. I did go looking for more comparisons, but performance comparisons appear to be harder to find than they were before. The ones I found were not talking about load speed, nor were they even talking about interface in any way, they only talked about algorythm execution speeds.

Having said that, I would expect that load times should be a bit slower than VB6 simply because VB6 is lighter. For example, I have a HEAVY resource-intensive app written in .NET. On my laptop, load times are kind of slow (LOADS of work happens during the launch, so the startup time resembles lots of games you see, though this is not a game). However, on a Surface 2 Pro the launch time is really fast. The systems are comparable as far as RAM, CPU, and so forth, so the difference in speed is probably due to the speed of accessing the solid state drive on the Surface vs the standard HD on the laptop. Performance once loaded is all you could ask for on either one, though.