They get a 882x speedup because hashcat's heavily optimized implementation of luks1 (aes, cbc-essiv:sha256, sha1) on a R9 290x GPU really is 882x faster than cr

They get a 882x speedup because hashcat's heavily optimized implementation of luks1 (aes, cbc-essiv:sha256, sha1) on a R9 290x GPU really is 882x faster than cryptsetup's ordinary implementation of this algo which runs on a single CPU thread when the LUKS key is encrypted during initialization. Note that LUKS by default sets the number of PBKDF2 iterations to take 1 second, not 2.