There is no latency constraint - it's a pure streaming operation, and total data to be transferred is 1 gigabyte for the whole set of vectors - which is well within the read performance of apples ssd's.

This is also the naive approach - there are probably smarter approaches by doing an approximate search with very low resolution vectors (eg. 3 bit depth), and then a 2nd pass of the high resolution vectors of only the most promising few thousand results.