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New Password Recovery Technique Uses CPU and GPU Together

BaCa writes to mention that a new hardware/software combination has been created by a company called ElcomSoft that will reportedly allow cryptography professionals to build cheap PCs that work like supercomputers for the specific task of retrieving lost passwords. Utilizing a combination of the CPU and the GPU the task of brute forcing a password may be reduced by as much as a factor of 25. "Until recently, graphic cards' GPUs couldn't be used for applications such as password recovery. Older graphics chips could only perform floating-point calculations, and most cryptography algorithms require fixed-point mathematics. Today's chips can process fixed-point calculations. And with as much as 1.5 Gb of onboard video memory and up to 128 processing units, these powerful GPU chips are much more effective than CPUs in performing many of these calculations."

52 of 264 comments (clear)

  1. What's the point? by jcicora · · Score: 3, Funny

    So what, will hackers be able to use my computer to crack my password 25 times faster now?

    1. Re:What's the point? by halivar · · Score: 5, Funny

      If they have access to your video card, they can peek behind the pixels to see what's under the "*******". I think. Or something.

    2. Re:What's the point? by morgan_greywolf · · Score: 2, Funny

      Oh noes! Then they will know my password!

      Wait! There must be some uses of this technology for pr0n.

    3. Re:What's the point? by FlyByPC · · Score: 4, Funny

      Heh. Little do they know that ********* is my password!

      --
      Paleotechnologist and connoisseur of pretty shiny things.
    4. Re:What's the point? by Anonymous Coward · · Score: 3, Funny

      All your **** are belong to us!

    5. Re:What's the point? by XHIIHIIHX · · Score: 3, Funny

      Yeah, but take the cover off the back of your monitor and there it is.

    6. Re:What's the point? by TheVelvetFlamebait · · Score: 2, Funny

      Heh. Little did they know that ********* is my password!
      Fixed that for you.
      --
      You know, there is a difference between trolling and pointing out the flaws in your reasoning. Just saying.
  2. Just wonderful by Tablizer · · Score: 5, Funny

    now IT departments will require passwords to be 30 characters long, with at least 2 digits, at least 2 puncuation marks, mixed case, and use Unicode characters from at least 8 different international languages.

    1. Re:Just wonderful by ScytheBlade1 · · Score: 5, Interesting

      I used to think the same. "Eight characters is enough for now, but it's only a matter of time..."

      Then I realized that this doesn't mean IT departments will require longer passwords. Rather, this is the death of the password, in place of other authentication methods (smartcard, biometrics, others, and combinations of everything).

      It won't be immediate, or close to it... but a 25x increase in the speed of bruteforcing passwords will certaintly speed up the process by which passwords are obseleted.

    2. Re:Just wonderful by justin12345 · · Score: 5, Funny

      I guess they are going to have to start making long, rectangular post-it notes now.

      --
      Cool art gallery, if you're into that sort of thing.
    3. Re:Just wonderful by ScytheBlade1 · · Score: 2, Informative

      That's not the problem. The problem is primarily people who gain physical access to the hashes, and load them onto much beefier machines to do the processing for them. 100% CPU for days on end will eventually warrant a call to the help desk stating that their computer is "too slow."

      While I agree that for this to be a problem, a previous security hole has to exist somewhere, it's more the "what if that happens" that is the problem. If a hash, and just a hash is stolen, it's not exactly going to set off alarms.

      Likewise, once unknown person X has your hash, it's over.

    4. Re:Just wonderful by sco08y · · Score: 2, Informative

      It won't be immediate, or close to it... but a 25x increase in the speed of bruteforcing passwords will certaintly speed up the process by which passwords are obseleted.

      It means the search space needs to be 25 times as big. That means the password needs one more letter.

    5. Re:Just wonderful by slyn · · Score: 2, Interesting

      I never got why people have so much trouble making up and remembering long passwords. I'm going to assume everyone here understands leetspeak, and enjoys something (i apologize to all the chronically depressed, i'm not trying to be an insensitive clod).

      If you like music, use lyrics and translate them into leet. Example: WelcomeToTheJungle becomes W31c0m3707h3Jung13
      If you like movies, use famous quotes and translate them into leet. Example: FranklyMyDearIJustDontGiveADamn becomes Fr4nk1yMyD34r1Jus7D0n7G1v34D4mn
      If you think your funny, use jokes and translate them into leet. Example: ThisWebServerIsASeriesOfTubes becomes 7h1sW3b53rv3r15453r13s0f6ub3s
      If you have need a password for root on /., use the tagline and translate it into leet. Example: NewsForNerdsStuffThatMatters becomes N3w5F0rN3rd557uff7h47m4773r5

      All these passwords are extremely easy to remember, and if you have a standard translation method (ie: 1 is always I and never L) you will prevent confusion that could lead to you forgetting your password. For added protection add symbols like Pipe for L or ? for Q.

    6. Re:Just wonderful by phantomcircuit · · Score: 2, Informative

      Or you could start using a more secure hashing function!

      The time it takes to calculate the hash is insignificant for a real user, but an increase of even a tenth of a second to an attacker could mean the difference between a day and a week to crack a hash.

      bluefish hashes take a long time (relative to md5 and sha1) to computer because the initialization takes a long time, there is no way to accelerate this initialization it must be preformed synchronously.

      OpenBSD FTW!

    7. Re:Just wonderful by wertarbyte · · Score: 2, Informative

      Anyway, since a network login can be done with a smartcard, why not an authentication mechanism using a USB stick drive containing the private RSA key?

      Because putting your pretty USB stick in a compromised system would void the security of your key. Anyone can just copy it an use it for himself. You can't do that with a smart card, since the key never leaves the card.

      --
      Life is just nature's way of keeping meat fresh.
    8. Re:Just wonderful by schmiddy · · Score: 2, Interesting

      Happily, it seems some companies are finally getting the message that longer passwords does not necessarily mean a more secure system. I know of at least one well-known security software company that has recently revised its stringent password policy from "super long, with numbers and punctuation, changed every 30 days" down to "less long, and you don't have to change it nearly as often".

      I'm guessing they had a security audit quietly done, wherein it was discovered that paying a janitor $20 to look for password Post-Its or doing a quick social engineering telephone call could break past more security than 100,000 CPU-hours of password cracking.

      --
      http://cltracker.net -- powerful craigslist multi-city search
    9. Re:Just wonderful by StressedEd · · Score: 3, Insightful

      There is nothing magical about biometrics, at the end of the day it is still a regular old password comprised of 1s and 0s
      Except that you can't change the password when it's compromised.
      --
      Be nice to people on the way up. You will meet them again on your way down!
    10. Re:Just wonderful by TheCarp · · Score: 2, Informative

      Right but the problem is that its really a l33tspeak filter on english.

      I tend to go a lbit more elaborate:

      w2tJwhF+G Welcome to the Jungle we have fun and games

      So each word accounts for 1 letter, often the first letter, sometimes whole words get changed.

      "Its better to burn out than fade away"

      Could be Bo>Fa

      and thats a good half a password right there...

      -Steve

      --
      "I opened my eyes, and everything went dark again"
  3. Government Motto by wildsurf · · Score: 4, Funny

    If brute force isn't working... you aren't using enough of it.

    --
    Weeks of coding saves hours of planning.
    1. Re:Government Motto by Bandman · · Score: 5, Funny

      it is important to realize that any lock can be picked with a big enough hammer.
      -Sun System & Network Admin manual

  4. From TFA: by Anti_Climax · · Score: 4, Funny

    For example, the logon password for Windows Vista might be an eight-character string composed of uppercase and lowercase alphabetic characters. There would about 55 trillion (52 to the eighth power) possible passwords. Windows Vista uses NTLM hashing by default, so using a modern dual-core PC you could test up to 10,000,000 passwords per second, and perform a complete analysis in about two months. With ElcomSoft's new technology, the process would take only three to five days, depending upon the CPU and GPU.
    I can't tell if the proper response to this is to recommend longer passwords or advise against using Windows Vista

    Oh wait, both.
    --
    Even people that believe in pre-destiny look both ways before crossing the street.
    1. Re:From TFA: by Otto · · Score: 4, Interesting

      Or to just stop using passwords. Why can't I login with a USB key that has some piece of information which is signed using my private key on it?

      --
      - Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
    2. Re:From TFA: by DeadBeef · · Score: 3, Informative

      If you are connecting to Linux or a BSD or anything else that runs openssh, then you can have something along these lines now. Setup an openssh DSA key, copy the public key to whatever machines you need to log into and then you can disable password logins in /etc/ssh/sshd_config altogether. If you are running Linux then for extra credit configure pam_ssh to get single sign on with an ssh key agent. If you are running windows as your client then you will have to make do with putty and pagent.

      Passwords are so last century.

      --
      I am a lawyer and this constitutes legal advice and I shall indemnify you against any losses arising from taking it.
    3. Re:From TFA: by blhack · · Score: 4, Interesting

      True, but it you create an easy way for a user to disable their own account this isn't as much of a problem. Create a 1.800 where you put in a (much easier) password that will allow you to disable access to your account. This way, if your key gets stolen, you just go into I.T. in the morning and have them issue you a new one.

      Not to mention the fact that when talking about password, your biggest enemy is some phiser sitting in russia....who is NOT very likely to fly to the states to steal your key. If your data actually is important enough to justify a hiring somebody to steal it, then chances are you are using biometrics/bullets to lock people out anyhow. If you're not, then tell you CIO to stop spending money on frosted glass NOCs that are suspended from the ceiling above your data center that is kept at a constant 42 degress and tell him to start spending it on real engineers.

      --
      NewslilySocial News. No lolcats allowed.
    4. Re:From TFA: by Deadplant · · Score: 2, Interesting

      Because USB is insecure.
      (assuming XP) When you plug in your USB key to login to your banking website it reads the signed key/password/whatever and signs you in. Great. Meanwhile... your screen-saver and the 'search bar' you installed also read your key and upload it to Mr. Nasty.

      What you would need is a USB key with a processor to do the signing/challenge response internally.

    5. Re:From TFA: by blhack · · Score: 2, Interesting

      No:

      lUser: 1.800.pas.swrd
      Phone Operator: Hello, this is Ryan in the I.T. department, how may I help you?
      lUser: Omg! i left my purse on the table in the restaurant, my key was in there....will you disable my account?
      Phone Operator: Sure may i have the password?
      lUser: The password is bananas
      Phone Operator: No, thats not the password, you only get two more tries before I call the number we have on file for this user and ask her what the problem is.
      lUser: AHHH AHHA AHHHHHH is the password, uhhh....... *click*

      --
      NewslilySocial News. No lolcats allowed.
  5. Pricing, What About SLI/CrossFire? by eldavojohn · · Score: 4, Interesting

    Pricing for these apps is pretty steep at $1,299 per machine license. Well, maybe not so steep if you consider how valuable it could be for you. It doesn't say if that has the GPU utilization with it yet or not.

    Also, I wonder if they've investigated using SLI & CrossFire with these. That seems like something obvious to me but not included in the article. I'm unaware of their implementation but it sounds like it could be parallelized--and accross 2 or even 4 cards, that could get hilariously powerful.

    --
    My work here is dung.
    1. Re:Pricing, What About SLI/CrossFire? by CastrTroy · · Score: 3, Interesting

      And how much more efficient is this than using http://en.wikipedia.org/wiki/Ophcrack">Rainbow tables. Using rainbow tables, Ophcrack can break passwords in seconds.

      --

      Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
    2. Re:Pricing, What About SLI/CrossFire? by Nathanbp · · Score: 2, Informative

      Nvidia's CUDA, which is what they're talking about, supports multiple graphics cards in the same computer. You don't actually use SLI, just run programs on multiple graphics cards. They've demoed systems with 3 8800GTXs (they take up 2 expansion card slots each, so you can't fit more than that in a single normal sized desktop case).

  6. Nice euphemism by otmar · · Score: 3, Insightful

    "Password Recovery" sounds so much more benign than "Cracking Passwords".

    Hello, Mr. Orwell. *wave*

  7. Finally, by Tablizer · · Score: 5, Funny

    I can now release the 12,000 monkeys I kidnapped for the task.

  8. How does this qualify for a patent? by Nathanbp · · Score: 4, Insightful

    What seems to have been missed in the discussion so far is that this company is applying for a patent on their technique, which they claim is "revolutionary." I really hope that this doesn't get granted, as it would open a whole new realm of stupid patents for "X on a graphics card," which is about as stupid a patent as "X on the internet."

  9. Not so new but still neat. by jshriverWVU · · Score: 4, Informative

    This project has been around for a long time: http://www.gpgpu.org/ Though I agree modern GPU's are even more useful for general purpose computing.

  10. Define "lost password" by frovingslosh · · Score: 2, Interesting

    I've read the article (such as it is), and it keeps claiming that this is a technique to recover "lost passwords". But I don't really believe that is the purpose of this software, and I have to ask "What is the difference between a 'lost password" and a password that belongs to someone else and not you?". Does anyone else really believe that the actual use of this software will be to assist the majority of users recover their own passwords? I do not. I suspect it might be harder to patent a tool for identity theft than for recovering "lost passwords" though.

    --
    I'm an American. I love this country and the freedoms that we used to have.
  11. What about FPGAs? by FlyByPC · · Score: 2, Insightful

    FPGAs (Field-Programmable Gate Arrays) sound like they would be just the ticket for SIMD (single-instruction-multiple-data) calculations such as this. Configure up a bunch of FPGA chips to do the encryption calculations on a zillion combinations in parallel...

    --
    Paleotechnologist and connoisseur of pretty shiny things.
  12. Cool, but a Linux Boot CD would be ALOT cheaper... by Zymergy · · Score: 4, Informative

    Petter Nordahl-Hagen's Offline NT Password & Registry Editor: http://home.eunet.no/~pnordahl/ntpasswd/
    NOTE: Tested on: NT 3.51, NT 4 (all versions and SPs), Windows 2000 (all versions & SPs), Windows XP (all versions, also SP2), Windows Server 2003 (all SPs), Vindows Vista 32 and 64 bit.

  13. Re:Elcomsoft by GiMP · · Score: 2, Informative

    This is the company with which Dmitry Sklyarov was employed at the time of his arrest by the FBI, back in 2001. Before his arrest, at a conference, Dmitry made a presentation on cracking Adobe's eBook DRM. The method used for this crack was utilized in Elcomsoft's Advanced eBook Processor software.

    This was really big news back in 2001-2002, although I guess thats a bit too long ago for most slashdot readers, since I (surprisingly) haven't seen any other comments mentioning this.

  14. Irony? ("...by a company called ElcomSoft...") by ClayJar · · Score: 5, Informative

    I'm just wondering, should I take the summary as intentionally ironic (i.e. as if it had referred to an operating system "by a company called Microsoft"), or should I assume it was written by someone *fascinatingly* oblivious to the recent history of decryption software and the disputed legalities thereof? An informed, non-ironic summary would simply say, "...by ElcomSoft...", of course.

    For any of you who may have been living under a rock (possibly on another planet), ElcomSoft is the company that was employing Dmitry Sklyarov, who was arrested in the US on DMCA charges when he'd come to present at a conference. Wikipedia has more.

  15. Pie in the sky hardware by dfn_deux · · Score: 2, Interesting

    Anyone car to point me to one of these mythical video cards with 128 processors and 1.5 gig of fast on board memory? Also, at the price point they are asking for this software (1200USD per seat) it seems like this is hardly cost competitive with doing this same sort of thing using commercially available FPGA dev/prototype boards and open source software designed for this EXACT task.

    --
    -*The above statement is printed entirely on recycled electrons*-
  16. Poorly written article by Deadplant · · Score: 5, Informative

    And with as much as 1.5 Gb of onboard video memory Not knowing the difference between a bit and a byte == Fail.

    ElcomSoft has discovered and filed for a US patent on a breakthrough technology ... harnessed the combined power of a PC's Central Processing Unit and its video card's Graphics Processing Unit. The resulting hardware/software powerhouse will... Referring to the (obvious) use of a new library/sdk from NVIDIA to improve performance of an existing application as the "discovery of a breakthrough technology" ==
    Fail.

    ...allow cryptology professionals to build affordable PCs that will work like supercomputers when recovering lost passwords. Cut and pasted from "How to write with spin for dummies"
    Fail.

    ...will be incorporating this patent-pending technology into their entire family of enterprise password recovery applications. Corporate press release copy and paste == Fail.

    Numerous grammatical errors == Fail.
    1. Re:Poorly written article by cdekadt · · Score: 2, Insightful

      Yes. It's terrible. All this company has done is use CUDA for what it was meant to be used. Big whoop. If they get a patent for it, it's really, really sad. And quite honestly, the number of passwords to test increases exponentially with length. It doesn't matter if they get a speed-up of 100x.

  17. Not really: just add 1 letter by Anonymous Coward · · Score: 5, Interesting

    Add 1 letter and you've increased the time it takes to hack by 26x (although it's probably closer to 100x with punctuation and the like). So 25x is irrelevant. So is 250x. Only something that makes it non-exponential would really make a difference.

  18. I'll take one of those! by unix_core · · Score: 2, Funny

    Hello, I would like to order one of your _cheap_ PCs, specifically the one with 128 GPU:s which I will turn into a supercomputer with this great software. I need it to recover my lost windows password. Thank you. And by the way do you still have those low-energy, standard socket 1.21 gigawatt bulbs?

  19. Interesting, but it doesn't matter by ZorbaTHut · · Score: 2, Interesting

    unless you're using a crappy password scheme like Vista's, for example.

    This is a process that lets you brute-force passwords 25 times faster. That's pretty neat, I'm not arguing that. It's extremely clever. But this speed [i]shouldn't matter[/i], because cracking passwords a mere 25 times faster shouldn't matter either. The problem comes down to how people are designing a lot of password schemes. They're aiming for speed. The article says the new technique can try ten million passwords per second on a single computer. Division tells us that, beforehand, the computer could process 400,000 passwords per second.

    When was the last time you had four hundred thousand users logging into a single computer per second?

    Checking a password should be slow. Brutally slow. I mean, quite literally, that just checking to see if the user's password hashes correctly should take at least a hundredth of a second. You're not going to have a hundred users logging in per second on a single computer anyway, our modern database-driven sites couldn't handle the load of displaying the login pages, so why are we making our password schemes so flimsy?

    If you use a slow password hash generation - and this can be something as simple as iterating MD5 over itself ten thousand times - whoever's trying to brute-force your password scheme is going to have a horrible, horrible time of it. Add a basic salt to the mix and you will not have anything to worry about from this. If your password checker takes a hundredth of a second, then 25 times faster means your adversary is going to spend $1300 on software in order to try 2500 passwords per second. If you have an appropriate salting system that's 2500 passwords for a single user. This is not the death knell for passwords, or anywhere near it. If anything, it's the death knell for crappy password hashes - but it's not even that, since you could trivially foresee things like this years in advance.

    Brute-force password cracking, by its very nature, is millions of times more expensive than merely verifying a valid user. From there, it's up to you to determine how safe you want your passwords to be. Personally? I'm fine with wasting a few extra hundredths of a second per user.

    --
    Breaking Into the Industry - A development log about starting a game studio.
    1. Re:Interesting, but it doesn't matter by flyingfsck · · Score: 2, Insightful

      All password checks on my machines take 10 seconds minimum. A strategic 'sleep(10)' does the trick. There is no need to calculate MD5 hashes repeatedly to waste an attacker's time. A nice sleep() allows the server to go do something more useful.

      --
      Excuse me, but please get off my Pennisetum Clandestinum, eh!
    2. Re:Interesting, but it doesn't matter by Anonymous Coward · · Score: 2, Insightful

      The "sleep 10" idea is pretty much a waste of your time to code unless you also limit the number of incoming connections. It would be fine in the old days with a dedicated connection to a serial port on the back of the computer, but now all an attacker has to do is open up a few hundred connections to your machine and multiplex the attack. The attacker will not care that at any instant 99.9% of his connections are in the "sleep 10" state, as long as he can find one of the connections that is ready to accept another password.

      http://utcc.utoronto.ca/~cks/space/blog/sysadmin/NetworkAuthDelays explains this issue, pointing out that all the delay does is annoy users who make typos, whilst not hurting attackers.

  20. Re:Can the GPU handle more diverse tasks? by Wavicle · · Score: 2, Interesting

    GPUs were foremost designed to execute large numbers of linearly-ordered simple matrix/vector operations per clock cycle. When it comes to generating 3D, there isn't much in the way of branching, recursion or conditional execution involved. I haven't checked recently, but it used to be that a "pixel pipeline" referred to a unit that could do a 4x4 * 4x1 operation in a single clock (16 multiplies and 12 adds).

    Coincidentally this also helps a large number of scientific applications, such as molecular dynamics, or physics applications that can be converted into vectors and manipulated, such as kinematics (this is what a physics engine often does).

    Game tree searches (I've written a few in my time) are usually highly recursive with exponential growth (branching factor). It would be very difficult to transform these into an efficient set of linearly-ordered vector operations. For example the static evaluator on many (older) chess engines consists of a painful set of heuristics and exceptions to heuristics, and exceptions to exceptions to heuristics. It is a very chaotic flow problem.

    --
    Education is a better safeguard of liberty than a standing army.
    Edward Everett (1794 - 1865)
  21. Ob. Bash Quote by 0100010001010011 · · Score: 4, Funny

    Cthon98> hey, if you type in your pw, it will show as stars
    Cthon98> ********* see!
    AzureDiamond> hunter2
    AzureDiamond> doesnt look like stars to me
    Cthon98> AzureDiamond> *******
    Cthon98> thats what I see
    AzureDiamond> oh, really?
    Cthon98> Absolutely
    AzureDiamond> you can go hunter2 my hunter2-ing hunter2
    AzureDiamond> haha, does that look funny to you?
    Cthon98> lol, yes. See, when YOU type hunter2, it shows to us as *******
    AzureDiamond> thats neat, I didnt know IRC did that
    Cthon98> yep, no matter how many times you type hunter2, it will show to us as ******
    AzureDiamond> awesome!
    AzureDiamond> wait, how do you know my pw?
    Cthon98> er, I just copy pasted YOUR ******'s and it appears to YOU as hunter2 ause its your pw
    AzureDiamond> oh, ok.

  22. Re:Something is wrong with computer priorities by julesh · · Score: 3, Informative

    Why is the GPU a processor dedicated to nothing but "pretty graphics" so much more powerful than the central multi-purpose processor even at the things like number-crunching?

    You need to rephrase your question, because it makes an incorrect assumption. Here:

    Why is the GPU a processor dedicated to nothing but "pretty graphics" so much more powerful than the central multi-purpose processor especially at the things like number-crunching?

    The answer is obvious if you think about it: those "pretty graphics" are a huge number crunching problem. That's all there is to it. GPU's, however, aren't very good at tasks that don't do exactly the same thing huge numbers of times. This is true of most applications. Including the applications that run on the PC to control what the GPU does in stuff like what the story's talking about.

    Is it because the GPU engineers can completely redo the thing from scratch whenever they want to, whereas the CPU-designers are held back by the backwards-compatibility issues?

    Partially. Modern GPUs have (I think -- I don't keep up to date) 256 bit wide memory interfaces, running at close to gigahertz speed. This means they can transfer to and from their memory at about 4 times the rate a PC can. This is possible because (1) graphics card manufacturers don't mind the types of memory they use changing on a virtually model-by-model basis and (2) they also don't mind being stuck with non-expandable memory that's soldered directly onto the card right next to the GPU.

    It's also because GPU engineers can sacrifice a lot of the flexibility of a PC. So what if the pipeline stalls if all 32 threads aren't doing exactly the same thing at the same time? Most of the time, they will be.

    Computer Science teaches, programmers aren't supposed to have to do "tricks" like this -- you code, and the translator (compiler or intepreter) will translate from your programming language to the hardware instructions.

    So why did my CS course have a module where we learned how the hardware worked? About memory hierarchies? About SISD, SIMD and MIMD processors? Why does Knuth's The Art of Computer Programming, possibly the most important book ever written on CS, approach problems at an assembly language level? Why, in my CS course, did I learn two different kinds of assembly language (one CISC, one RISC)?

    Because CS is concerned with a holistic view of computers. With the fact that they are machines for executing instructions, and what can be done with those instructions. With the fact that it may be more efficient not to specify that much detail, but also the fact that, from time to time, you do need to do that.

  23. ElcomSoft by Anonymous Coward · · Score: 2, Interesting

    a company called ElcomSoft

    How short Slashdotters' memories are. ElcomSoft is the Russian company Dmitry Sklarov was working for when he wrote the ebook software that got him thrown in jail when he visited the USA, after Adobe made a DMCA complaint against him.

  24. Re:Can the GPU handle more diverse tasks? by smallfries · · Score: 2, Interesting

    GPUs were foremost designed to execute large numbers of linearly-ordered simple matrix/vector operations per clock cycle.

    Minor correction - I know what you mean when you say "linearly-ordered" but a more accurate way to describe it would be: large sets of independent operations per clock-cycle. The sequential encoding that happens between clock cycles is true of most processors, and not specific to GPUs. The key is high performance is the lack of communication between separate instances of the pixel shader which is a property of the independence of the sub-problems.

    You're right about the chess search, in contrast to what the poster above you claims, a GPU would not be suitable for evaluating the heuristic because of the branching control flow within the heuristic. An interesting scoring function would be to try and encode a neural network that can score the position: then data packing would be an issue but a neural net can be converted into very efficient GPU code as long as the number of pixels that you are gathering the position from is quite low.

    The real performance killer would be the scatter at the other end - once a position is scored the card needs to perform sorting to filter out the high scoring positions from the low. This sorting may be avoidable on the newer CUDA cards as their memory architecture allows an efficient scatter without the need to sort data.
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  25. PS3 by ilitirit · · Score: 2, Interesting

    Anyone ever considered using the PS3 for stuff like this? Seems like you have all the processing power you need (relatively speaking), but what else would you need to take into consideration?