If you are talking latency influences during rendering of the final product output (to file), then sure - the output speed (rate of file creation) may and probably will be influenced. However - soon as you start saying that the final output quality (in a file/s) is influenced by latency of the drive I am not a firm believer in that - as Richard rightly said earlier, THAT process MUST be deterministic, and as long as its NOT for any given circumstance there is imo something way more basic wrong there somewhere.

Moving material/data off the C drive onto a separate partition on the same physical drive can only ever increase your noted latency hassles (if they do exist) because you are in effect FORCING the worst possible latency issues into the equation

I can see realtime playback to the monitor from a TL consisting of a multitude of different small files/transitions/effects possibly being influenced/affected, but I am willing to bet that the CPU and GPU will still be the governing factors even under those conditions with Studio products.

I usually make a AVCHD file first to have a continuous stream,(then use tsMUXER) many times I have to redo some segments because of momentary minor breakup, perhaps 5 to 10 frames that show some pixelation. My guess is that the hdd head was not tracking precisely at that instant, thus reducing the S/N ratio. I just shudder to think what the track width might be.