Float vs Double Performance

I did some timing tests and also read some articles like this one (last comment),and it looks like in Release build, float and double values take the same amount of processing time.

How is this …

sizeof(int) on x64?

When I do sizeof(int) in my C#.NET project I get a return value of 4. I set the project type to x64, so why does it say 4 instead of 8? Is this because I’m running managed code?