Tesla K20m sha512crypt dictionary attack performance issues
Please note: I'm an oclHashcat newbie, I don't want to complain, I'm just asking and trying to make my points clear.

(02-24-2014, 02:04 PM)epixoip Wrote:
(02-24-2014, 01:51 PM)afra Wrote: The REAL issue is why a system with half the video cards performed as fast as mine.

that was with a different program, with likely a different driver, so you're not really comparing apples and apples.

Sure. I wasn't expecting a 100% matching result, and I wasn't expecting 2x speed with double the cards, since I understand not everything can be perfectly parallel.

I wasn't expecting such a performance drop, either . It's true that oclHashcat-lite was a different program, but since it was merged into oclHashcat I was hoping for the performance to be more-or-less the same.

I was able to retrieve a copy of oclHashcat-lite 0.15 and it scores about 370MH/s in benchmark mode; so I guess it's actually a an oclHashcat vs oclHashcat-lite difference.

(02-24-2014, 02:04 PM)epixoip Wrote:
(02-24-2014, 01:51 PM)afra Wrote: And about the speed: I think you're unfair to me :-) I wanted a) a very stable system that could be left unattended, and b) a system which cracked sha512crypt hashes effectively. AFAIK Nvidia is as fast as AMD regarding sha512 hashes.

"a" was a valid point several years ago, but nowadays amd gpus are just as stable and reliable on linux as nvidia gpus. as for "b", no, nvidia is not as fast as amd on sha512 hashes. even with the 55% loss in 64-bit performance compared to previous generations, the R9 290X is twice as fast on sha512 as your Tesla at 1/5th the price.

In our scenario, reliability is king. I won't enter into details, but we needed something that we could put in a remote data center and just call the support if something bad happened. We looked for somebody who could provide us with a fully supported ATI based cracking box, but we were not able to find one.

The most famous company which specializes in GPU hardware and would provide us with a Radon based solution, for example (I'm not saying the name since I don't know whether I'm allowed to), gave us just a 1-year warranty for graphic cards, and the hardware support said that we had to send back the whole server to them for repairs.

On the contrary we were able to find a 5-year-warranty Tesla box with 24x7 support that gives us the warranty of an on-site intervention and an hardware fix within 8 hours. Moreover, the 4x Radeon 7970 box would have been faster, but the total system price was in the same range (+/- 1.000 EUR) of the Tesla K20m. Sounds strange? If I can remember it right, the Radeon company told us that the high price was because they hand-picked the most reliable 7970 cards for the task and they adopted a custom cooling system.

I knew that the Tesla were slower, price-wise, than the Radeon solutions: I just didn't think that they were THAT slow, based on the benchmarks that were available to me at the time.

Anyway, everything seems normal and there's not so much space for improvement unless new versions of oclHashcat get better; I'll try running a matching benchmark on oclHashcat and oclHashcat-lite and maybe opening a ticket to the authors explaining the notable difference (maybe it's just a small glitch that wasn't highlighted since cuda is a bit of second-class citizen in oclHashcat).

Thank you for your explanations and support!

Messages In This Thread
RE: Tesla K20m sha512crypt dictionary attack performance issues - by afra - 02-24-2014, 02:33 PM