comparing native 8bit add vs 8bit->16bit add->8bit. only a modest change... 7.5 gb/s vs 6.5 gb/s
increasing data size doesnt really change any sped information
back to sanity
16bit -> 32bit test. same tradeoffs as with 8->16. but, all 2x slower (same gb/s), mem bounded.
8bit -> 32bit add -> 8bit isnt too slow. still 5.9 gb/s, and that's in terms of uchars. sweet. (tl;dr, it's fine to go up to 32bit, so long as we can quantize the result ot 8bit