I'm not really sure, I don't really understand what he means. With knowledge of the server seed, it probably only takes a few hundred CPU cycles to figure out the required client seed to win. (let x be a random number in the winning range. Then use a client seed of:  (x -serverseed) % 2^32.   Or i mean, if you're lazy and want to brute force a client seed -- there's only 4 billion possibilities, and it's a simple range check, so you can scan the entire range in under a second. But you don't even need to scan the entire range, as there's probably at least 50 possible client seeds (if you're randomly searching) so it's an extremely fast operation.