Ok, this was a pretty dumb post. This example that I found seems to be incorrect. The value for the period isn't in nanoseconds, but in picoseconds, so the correct value would actually be 500000. 500 picosecond period would mean a frequency of 2 MHz, which is way too high. The problem wasn't that the LED took too long to update, but that the resolution at this frequency was way too low.
