What program is quickest at processing and writing OCR information? The source file is a PDF, which I want to turn into a searchable PDF.
I am okay with sacrificing some accuracy at the expense of speed.
I prefer OS X applications.
If you wanting to work with lightning fast OCR recognition on your Mac then you should check out the LEADTOOLS OCR app for OS X. The LEADTOOLS OCR engine is one of the fastest character recognition engines and the linked application is a demo of it. The OCR engine can also be optimized for faster speeds with enhancements using various image processing commands which will result in better recognition as well which you can read about here.
Disclaimer: I am an employee of this product