
Originally Posted by
Packetdancer
So, the 2013 iMac has an Nvidia GeForce 775M, if I remember right. That's a bit of an older card, but FFXIV only requires a GeForce 400 series. That'd be more than sufficient for running FFXIV on Windows as well. Unfortunately, I cannot tell you offhand what the exact performance improvement will be, but there will be an improvement. To elaborate (feel free to skip the rest of this post if you prefer)...
The 'Mac' version of FFXIV actually is the Windows version, running through Crossover. Crossover is a translation layer that lets Windows applications run on Mac. To elaborate, the 'brain' of a Windows installation and a Mac installation—the CPU on which it runs—is the same; the two operating systems are like different languages, and the programs are like books. If the computers were people, then everyone has a brain (we assume), but they don't always speak the same language.
If you have a book in Japanese and a reader who only speaks English, they need someone to translate it for them. That's what Crossover does.
The problem is, just like having someone translate a book for you takes longer than just reading it, the Crossover layer does introduce a little bit of overhead to each call. And that does have a performance impact. If I ask the DirectX graphics system on Windows to do something, that request just goes right to DirectX. With Crossover running a Windows application, the request goes to Crossover, which turns it into one appropriate for a Mac. (Or, in this case, it uses DXVK to turn it into a Vulkan call, which uses MoltenVK to turn it into a macOS Metal call...)
If you use Boot Camp, all that does really is provide a bootloader that lets you boot between Windows and macOS, and the drivers/software so you can access your files in both operating systems. In effect, your computer becomes bilingual; booting into Windows means the program just runs without any extra effort. The upshot of which is, yes, there will definitely be a performance gain running on Windows.