hashcat speed when using a text file of NTLM hahes

[remoteview]

Hi all,

We built a crackstation. When passing a single NTLM hash to hashcat, I average around 1200 GH/s.  However, when I change the hash to a text file containing two NTLM hashes, the speed drops to around 500 GH/s.  When I change the hash to a text file containing 25,000 NTLM hashes, the speed again drops to 500 GH/s.  This doesn't seem right and I wanted to inquire if anyone has tips or suggestions. 

Thanks!

[penguinkeeper]

Nice speed! This is perfectly normal and is due to some of the optimisations that are lost when you go from a single hash to multiple. With a single hash, we can reverse parts of it so most of the time, your GPU(s) don't actually need to perform the full hashing calculations, whereas for 2 or above hashes, Hashcat can't do some of these optimisations, like the one I mentioned, called "Early Skip".

[remoteview]

Thank you!