In a test, the researcher’s system was able to churn through 348 billion NTLM password hashes per second. That renders even the most secure password vulnerable to compute-intensive brute force and wordlist (or dictionary) attacks. A 14 character Windows XP password hashed using LM NTLM (NT Lan Manager), for example, would fall in just six minutes, said Per Thorsheim, organizer of the Passwords^12 Conference.

via Update: New 25 GPU Monster Devours Passwords In Seconds | The Security Ledger.