PS. Kraken will use all available CPU cores (of course), when using the CPU based code. Using it, with a high end multi-core machine, does not even come close to using a GPU.
On Wed, Mar 26, 2014 at 5:58 PM, Joel Eriksson <joel.eriks...@gmail.com>wrote: > Radeon GPUs were originally made by ATI. ATI was later acquired by AMD, > but the GPUs are certainly not AMD CPUs and the performance when it comes > to the kind of computations that are required for A5/1 and crypto in > general is not even close when you compare CPUs and GPUs. The reason for > this is mainly because in a single GPU, there are actually up to thousands > of cores that performs the actual computations. In the case of Radeon HD > 6990, for instance, you have 2 GPUs that have 1536 cores each, so 3072 > cores in total. Compare that to an ordinary CPU, and you realize that a > multi core CPU does not even come close. :) > > So no, it's not about using the GPU to get some extra power instead of > just letting it sit idle. GPUs are way, way faster than CPUs for this kind > of stuff. For a bit more detailed information about why this is the case, I > advise you to read this: > > https://en.bitcoin.it/wiki/Why_a_GPU_mines_faster_than_a_CPU > > Quote: > "A CPU core can execute *4* 32-bit instructions per clock (using a > 128-bit SSE instruction) or *8* via AVX (256-Bit), whereas a GPU like the > Radeon HD 5970 can execute *3200* 32-bit instructions per clock (using > its 3200 ALUs or shaders). This is a difference of *800 (or 400 in case > of AVX) times more instructions per clock*." > > Specifically, AMD/ATI GPUs are the best suited for these kinds of > computations, which is why they are used rather than NVidia based cards. > This is because AMD/ATI cards (once again, GPUs, not CPUs ;) have a number > of features that make them well suitable for high performing integer > operations. Traditionally, GPUs are better suited for floating point > operations because that is more important for gaming/graphics performance > in general. If we take Bitcoin mining (i.e SHA-256 computations) as an > example, the Radeon HD 7970 is about five times as fast as the GTX 680. > > Regards, > Joel Eriksson > clevcode.org > > > > > > On Wed, Mar 26, 2014 at 5:39 PM, Nikos Balkanas <nbalka...@gmail.com>wrote: > >> >> >> >> On Wed, Mar 26, 2014 at 5:12 PM, Joel Eriksson >> <joel.eriks...@gmail.com>wrote: >> >>> Using CPUs instead of GPUs doesn't make any sense at all, CPUs are a >>> _lot_ slower than GPUs for these kinds of computations and you would need a >>> cluster (i.e much more expensive) to be able to get similar performance. >>> >>> >> You don't need a cluster for a multiprocessing board. Just a >> multiprocessing kernel that linux provides. Radeon's GPUs are, to my >> knowledge, AMD CPUs, but at lower frequencies. Granted, you don't have a >> general kernel running on top of them, but an MP kernel has load balancing >> and preemptive multitasking that kraken hasn't. ;-) >> >> But we are in agreement here. If you have a GPU sitting idle, why not >> take advantage of it? >> >> To really crush both CPUs and GPUs, you could create an ASIC for it >>> instead. I bet that there are A5/1 cracking ASICs out there already, just >>> not in the hands of the public AFAIK. Using FPGAs would be a decent middle >>> ground. >>> >> >> Yeap. >> >>> >>> Cheers, >>> Joel >>> >>> >>> On Wed, Mar 26, 2014 at 2:22 PM, Nikos Balkanas <nbalka...@gmail.com>wrote: >>> >>>> >>>> >>>> >>>> On Wed, Mar 26, 2014 at 1:51 PM, Joel Eriksson <joel.eriks...@gmail.com >>>> > wrote: >>>> >>>>> It will be _a lot_ slower. If you want to have any chance of >>>>> intercepting frequency hopping calls (without having receivers constantly >>>>> recording everything at each of the possible frequencies) you need to use >>>>> GPUs and SSDs. If you don't have to deal with frequency hopping, and don't >>>>> have to decipher in near real-time, it doesn't matter as much. >>>>> >>>>> Regards, >>>>> Joel >>>>> >>>>> >>>> In such case, wouldn't it make more sense to have more CPUs on the MB? >>>> >>>> >>>>> On Wed, Mar 26, 2014 at 11:36 AM, Nikos Balkanas >>>>> <nbalka...@gmail.com>wrote: >>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Mar 26, 2014 at 8:40 AM, Amber and Sarosh < >>>>>> amber_sar...@hotmail.com> wrote: >>>>>> >>>>>>> Hi All, >>>>>>> Can anyone please guide if GPUs are necessary for rainbow table >>>>>>> lookup using kraken to find the key to decipher an intercepted >>>>>>> communication or is it possible to do this using just CPUs? In case the >>>>>>> later is possible how much time it will take approximately? >>>>>>> >>>>>>> >>>>>> GPUs are not necessary, just desirable. If GPUs are missing, kraken >>>>>> will still work with A5Cpu.so, but it will be somewhat slower. Assuming >>>>>> that during cracking your PC is CPU limited, the benefit should scale >>>>>> roughly with your setup ratio of GPU power/CPU power. In reality you will >>>>>> run into RAM and table I/O bottlenecks before that. In short it is highly >>>>>> depended on your setup ;-) >>>>>> >>>>>> The idea is, that the easier factor to improve is the CPU, so why not >>>>>> do it? >>>>>> >>>>>> Nikos >>>>>> >>>>>>> Regards, >>>>>>> Naheed, Amber & Sarosh >>>>>>> >>>>>>> _______________________________________________ >>>>>>> A51 mailing list >>>>>>> A51@lists.srlabs.de >>>>>>> https://lists.srlabs.de/cgi-bin/mailman/listinfo/a51 >>>>>>> >>>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> A51 mailing list >>>>>> A51@lists.srlabs.de >>>>>> https://lists.srlabs.de/cgi-bin/mailman/listinfo/a51 >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> Best Regards, >>>>> Joel Eriksson >>>>> >>>> >>>> >>> >>> >>> -- >>> Best Regards, >>> Joel Eriksson >>> >> >> > > > -- > Best Regards, > Joel Eriksson > -- Best Regards, Joel Eriksson
_______________________________________________ A51 mailing list A51@lists.srlabs.de https://lists.srlabs.de/cgi-bin/mailman/listinfo/a51
