The load factor of a hash table is defined as the `elements in hash table / number of buckets`. Once the load factor is reached then the table is doubled in size. The default value is typically around 0.75, but the hash table in the RTS has a fixed load factor of 5. This number is just unusually high, it will lead to less memory being used but also common collisions. This ticket just notes the unusual choice made. cc @fendor