First of all, thank you very much for joining our Forum and being willing to Support us in such a Major way. That is incredibly nice of you.
Furthermore, you may take a look at the current source Code and compilation methodology here and here.
Secondly, thank you very much for Clearing up the licensing question. Just for legal reasons, may I ask whether it would be ok to use your source Code, obviously with proper Attribution under the MIT license?
Thirdly, the x86 vs x64 Speed inconsistencies are likely caused by the requirements for extending the string lenght when running AMD64 based Systems in 64-Bit mode while the string lenght doesn't fully utilize more then 32bits causing an increased requirment in using Cache which doesn't yield any improvements while limiting the small amount of low Level Cache available on most consumer CPUs. That though is only a hypothesis. Maybe I simply misunderstood something my CS teacher told me, though that's how I recall his reasoning on certain aspects of x64 being slower then x86.
Again, thank you very much for your help, if you have any questions or require anything, don't hesitate to ask and have a great day,