By default in 2009, Snow Leopard boots into a 32-bit kernel, an odd proposition for an OS claiming to be 64-bit. But Apple defaulted to a 32-bit kernel for good reasons:
- it keeps compatibility high with drivers and specialized software, which lowers hassles for users;
- it keeps bad press away. Like bad breath, bad press makes a lasting first impression. Microsoft halitosis (also known as Windows) turned off a lot of users. (I think Microsoft should change the name, it’s a perfect fit!). performance is still improved over Leopard.