john-users - recommended way to crack a descrypt hash in a multi-gpu setup (HD 7990)

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Date: Tue, 22 Apr 2014 23:30:04 +0000
From: yungai <BM-2DBq3nJF7GXKr6Nk6EHzvxxGBec6gQn2NB@...message.ch>
To: john-users@...ts.openwall.com
Subject: recommended way to crack a descrypt hash in a multi-gpu setup (HD
 7990)

Hi there,

in recent thread I read about the --fork feature in conjunction with
GPUs but simply trying --fork=2 didn't work for me (running a current
bleeding-jumbo git version).

So I wanted to ask you what the recommended way to crack a hash with
multiple GPUs currently is?

second question:
What kind of performance can one expect when cracking descrypt on a HD
7990? I remember seeing benchmarks on john-dev(?) with ~102000 Kc/s but
I can't seem to find that benchmark anymore

I get on my HD 7990 (with device 0):
~47000 Kc/s

so that would be near the value I remembered if you multiply that by two
for the second GPU.

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