The PIC that was are looking to use is the 18F2550. We don't need a many I/O, just a handful and a USB port. The only reason I could possibly think to use a faster oscillator is for better accuracy. Does it not make sense that to say an oscillator running at 4 MHz +/-50 ppm will be less accurate than one running at 20 MHz +/- 50 ppm due to multiplying less to achieve the same results?
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