Increasing MD5 GPU Utilization?

[protocol]

you can use the known text at the beginning as a salt and use md5(salt.pass) mode.

Thanks to epixoip and undeath for that explanations and tips.

I have re-worked it to use md5($salt.$pass) and now the time to test the key space has fallen from 10 days to 6 hours.

Session.Name...: oclHashcat
Status.........: Running
Hash.Type......: md5($salt.$pass)
Time.Started...: Tue May 13 11:40:57 2014 (1 min, 11 secs)
Time.Estimated.: Tue May 13 17:50:55 2014 (6 hours, 8 mins)
Speed.GPU.#1...: 5172.5 MH/s
Speed.GPU.#2...: 4702.6 MH/s
Speed.GPU.#*...: 9875.1 MH/s
Recovered......: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.......: 699526021120/218340105584896 (0.32%)
Skipped........: 0/699526021120 (0.00%)
Rejected.......: 0/699526021120 (0.00%)
HWMon.GPU.#1...: 99% Util, 73c Temp, 89% Fan
HWMon.GPU.#2...: 99% Util, 65c Temp, 76% Fan

CTu2y, I believe that it should be possible for you to use md5($salt.$pass) as well.

You could try modifying your hashes to the required mode 20 format, using 199 as a salt. For example;

6xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx5:199

then test against ?d?a?a?a?a?a?a
For me the speed increase was dramatic.