cracking performance doubts

[raist2]

Sorry if I'm asking something know, i've some doubts about the performance of my 7970.
I use ubuntu linux, a dual core xeon, 8 gigabyte of ram and 3 7970.
What I see is performance for all my three 7970 being 15/20% (on DES even more) slower than what is shown in web site main page performance table.
This happen for both hashcat-lite and hashcat-plus.

What i'd like to ask is:
1) does operating system matter? windows driver are better than linux ones?
2) does ram and CPU matter? maybe for password candidate generation and I/O thru the GPUs?
3) are the reference values (in hashcat main page) calculated with the benchmark option? if so, can those values be different from real life cracking?
4) which is the reason behind multi-hash speed decreasing so hard when the hash list grows?

I'd greatly appreciate if some one would answer point by point.
Regards,
Raist

[mastercracker]

1) No, OS does not matter.
2) Neither does RAM or CPU.
3) Not sure, wait for Atom or philsmd answer
4) Not 100% sure but probably more memory swapping.

[jb_bak]

Hashcat 15 is slower than 14.

have you tried overclocking? i've got your same setup, except 4 7970s. I've got them at 1165 with no probs.

aticonfig --adapter=all --odsc=1165,1050 --od-commitclocks

[epixoip]

1) does operating system matter?

no.

2) does ram and CPU matter? maybe for password candidate generation and I/O thru the GPUs?

no. password candidates are generated on the gpu.

3) are the reference values (in hashcat main page) calculated with the benchmark option? if so, can those values be different from real life cracking?

every attack mode shows different performance in different circumstances. the numbers provided on the site are for reference only. YMMV.

check your -n and -u values, optimize your dictionaries by sorting them by length, make sure you're giving the cards enough work.

4) which is the reason behind multi-hash speed decreasing so hard when the hash list grows?

GPU memory.

you will really only see this on AMD and older Nvidia cards. newer Nvidia cards have a much better memory controller, and they have a large L2 cache, so there isn't as much of a performance hit on large hash lists.

[atom]

for oclHashcat-lite, performance numbers have been generated with -b --benchmark-mode 1 option.
for oclHashcat-plus, performance numbers have been generated with epixoip's benchmark script for oclHashcat-plus.

For both numbers, they can be seen as real-life situations. Make sure your GPU's have enough work to do and you're using optimized -n and -u value (try out).

[raist2]

Thanks Epixoip but this is sending me crazy.
I still wonder how a stock 7970 can reach 83976.8k c/s of DES with oclHashcat-lite when my cards are like this (-n 120 -u 1024):
core at 925 Mhz
Speed.GPU.#1...: 61032.5k/s
HWMon.GPU.#1...: 99% Util, 59c Temp, 51% Fan
----
core at 950 Mhz
Speed.GPU.#1...: 62623.0k/s
HWMon.GPU.#1...: 99% Util, 48c Temp, 36% Fan
----
core at 1000 Mhz
Speed.GPU.#1...: 65954.4k/s
HWMon.GPU.#1...: 99% Util, 44c Temp, 0% Fan
-------
Do anyone reached reference performance, at least for DES?
For MD5 and NTLM my performances are a little bigger than reference, I'm wondering if DES stats could be wrong.
Regards
raist


PS. I edit this message because I noted something weird in reference stats...
Comparing 6990 and 7970 performances the 6990 is almost faster due to its dual core.
This doesn't happen only for DES and LM performances.... I really believe that at least DES 83976.8k c/s is wrong...

[raist2]

Hashcat 15 is slower than 14.

have you tried overclocking? i've got your same setup, except 4 7970s. I've got them at 1165 with no probs.

aticonfig --adapter=all --odsc=1165,1050 --od-commitclocks

Thanks, I was wondering how to overclock in linux and you greatly helped!
This not solve me to reach 84 Million for DES as reference but gived me a great boost
raist

[epixoip]

i get about 60 MH/s, so it's not you. you can stop worrying now.

[atom]

DES performance is massively influenced by the driver. If you use one of the newer ones, DEScrypt speed will change.