Most of the cost of string checks is often just the cache miss to load the first bytes of the string. Depending on the input, e.g. if lengths have more or less

Most of the cost of string checks is often just the cache miss to load the first bytes of the string. Depending on the input, e.g. if lengths have more or less uniform distributions, full string checks might only be needed 10% of the time or so; store the string length in the bucket and you save the cache miss. Or you could store the first few bytes of the key in the bucket (but then in other cases, for example a hash table containing absolute filesystem paths, the first few bytes are always the same across keys).