A PC rig that belongs on the wall of an art museum

When Overclock.net user [Show4Pro] decided to upgrade his “old dusty rig”, he eschewed the conventional PC form factor and instead built an incredibly sexy custom wall-mounted case.

The six sticks of RAM, quad HDD/SSDs, and dual Radeon HD7970s are enough to make all but the most hard core gamer blush, but that was only the beginning here.  Using a Dremel tool, Show4Pro cut the frame from a piece of hardboard and coated it with a mock-carbon fiber vinyl sheet.  This backdrop acts to both hide the (many) cables and provide structural support to the components.  Custom light guides cut from an acrylic sheet are back lit with LEDs and serve as a border for each of the components.

Laying all of the boards flat on the frame required the use of PCIe risers to move the video cards away from the mother board.  Long PCIe connectors are very susceptible to EMI though, and Show4Pro ran into a few stability problems that he eventually had to resolve with some high-end shielded risers.

Besides that one minor hiccough, the project went off without a hitch and it looks like his 100+ hours of work have really paid off.

Via Reddit.

Comments

  1. andres says:

    pci-e uses differential signalling. Shouldn’t the pci-e rises be using twisted pair cables?

    • andres says:

      risers*

    • AKA the A says:

      The flat cable works for most of time if kept reasonably short and is dirt cheap, so that’s what Chinese manufacturers are making ;-)

    • Fried Chips with Ketchup says:

      Thought the same, but then I googled and found PCI-E impedance = 100Ohm and normal ribbon cable impedance =120Ohm, so not that much of impedance mismatch

    • defaultex says:

      Ribbon cable works pretty good for most instances where you need twisted pairs. When I modded my Xbox360 with a VGA port I used ribbon cable and put a ground between the RGBHV lines. I was surprised it worked considering how sensitive the VGA coming out of an Xbox360 is to noise.

      • adcurtin says:

        Yeah, when I made a xbox 360 AV to VGA cable, it had really poor quality video until I salvaged a cable shield and put it on this cable and grounded it well to both ends. It was a little surprising.

        • Daniel says:

          I’m not real great with the shielding stuff, but aren’t you only supposed to ground one end of a shielding cable? Isn’t that what they do with USB?

          • pcf11 says:

            We have a special word for a conductor grounded on one end, it is called an antenna.

          • Daniel says:

            Can you explain why they do it with USB in simple terms then? This is what I’m referring to: http://www.microchip.com/forums/m267325-print.aspx

          • pcf11 says:

            I cannot explain because I have never given it any thought, nor do I have any knowledge of the matter. I’m sure whoever designed USB had their reasons for doing things how they did them. I can only speculate as to exactly what those reasons were though. Maybe to protect against ground loops, or to isolate one device from another which may have a higher potential ground? Perhaps something else entirely. I’ve no direct experience working with USB beyond plugging devices into the ports, like many others do. I still like parallel ports better. I’ve made a port buffer for one of those too.

            I can say this now, the metal shields on both ends of a USB printer cable have continuity between them. I just measured it with an ohmmeter here. So whatever hocus-pocus going on is going on inside the devices themselves. For now I’ll take it an an article of faith that one end is not connected to a chassis ground based on what I’ve read at the link you’ve supplied.

            Mostly because I’m not interested enough right now to rip open a printer, or something to investigate further. USB really isn’t my bag, I’m sorry.

          • Garbz says:

            You’re right in that grounding at one end effectively makes a cable an antenna, that is exactly why it is important to ground at and end with low-impedance and not at the end with the sensitive receiver circuit.

            It’s ultimately a trade off and ideally you design systems where ground potential is equalised and return currents never travel across the shield, but in cases where this isn’t possible like most single ended circuits it is far more preferable to have an antenna going back towards the transmitting device than it is to have a ground loop. It’s quite application specific.

    • tekkieneet says:

      They tends to wire 2 ribbon cables, one from side A and one from Side B
      in those risers. The PCIe pinout if you look at Side A or B has 1 or 2
      grounds on both sides of a differential pair to isolate them from other
      signals. This arrangement is pretty good for signal integrity.

      The ground as a shielding effect for capacitively coupled noise and the
      extra separation to reduce magnetically couple noise. The ground signals
      also work as return path should there be some slight mismatch in the
      differential drivers.

      Twist pairs are used when you want external noise coupled to both wires
      in a more or less equal manner. Due to the grounding arrangement, that’s
      not a big issue.

      The part that ribbon cables isn’t spec for high frequency and more so
      for the Chinese cables. Who knows what attenuation/impedance
      characteristic looks like over the frequncy. But hey it is less than
      $10.

      • Joel Severin says:

        (To be honest, I wouldn’t even dream of this being possibe after reading some of the PCIe-spec. I mean, even… look att the requirements for PCBs… But I guess the free space around the cabes is the thing that makes this work.)

        One thing I don’t understan is why ground would work good as an “insulator”… I would understand it, if it was connected only in one end. But if it is on both ends, wouldn’t it let through a current of (sum of all incoming current)/(number of return ground wires)? Let’s take an example of an on-board GPU fan, it would draw current from the +5v in the cable and then return current through all ground wires, probably in an equal fashion as all wires have roughly the same resistance.

        I’m a beginner in electronics, so I could be wrong anywhere and everywhere ;)

        • pcf11 says:

          Did you see isolate and read insulate? The author maybe should have used the word shield. As grounds used to block interference are usually called shields. Either that or I’m seeing things.

          • Joel Severin says:

            Hmm, I didn’t even know there was a difference between isolate and insulate (in Swedish, which I’m natively speaking, they mean the same). What I really meant was “something between that will block interference”.

        • tekkieneet says:

          It is a matter of geometry, if your interference is from a far distance
          relative to the separation between a diff pair, even on a flat cable the
          distance from it hence (magnetic) coupling would be more or less the
          same.

          DC current would be distributed based on the DC resistance while AC
          (high frequency) current by the impedances. Roughly speaking the
          “shortest” path would have lower inductance and carry more of the
          current.

          • ChopSueyAR says:

            “Roughly speaking the “shortest” path would have lower inductance and carry more of the
            current.”

            Can you break this down/explain this further (Pretend I’m in 4th grade)?

          • tekkieneet says:

            Essentially, the larger the current loop (from the signal and its return
            path), the higher the inductance there is. So AC current tries to flow to
            minimize this.

            e.g. If you have a signal and ground right next to each other on a
            ribbon cable and some other grounds further away. The “shortest” path
            for the return current would be the ground wire right next to it as the
            return current would flow in an opposite direction canceling some of
            the inductance.

            The actual math/physic is 1st years University level stuff and covered again in 2nd years.

          • Joel Severin says:

            Not really what I meant… It was more that it might be stupid to have sources of interference near the signal cables, even if they are in a diff-pair. (Or Isn’t it?)

            And why would it not matter? Let’s say the separate cables in the flat cable are laid out like |a||b||c|. Wouldn’t the a-cable in the diff-pair a|b be affected at least half of what b would be (or, rather, exponentially as the field attenuates with (distance)^2 or something like that)?

            I think I missed an important point in my first post: the GPU fan is PWM-controlled. I didn’t think about that DC currents don’t cause electromagnetic interference, so let’s add that. The fan was just an example anyway to have something to visualize, there can obviously be a lot of other things that turn on and off on a graphics card.

            We can probably assume that the grounds are connected together on both ends of the flatcable and that each individual cable component is equal => the current paths all have the same impedences. So there would indeed be some current through the ground wires (approx. the same for all). The question here becomes either:
            * Does the ground not interfere with the diff-pair that much at all to make a difference, even in a PCIe-bus?
            (or, if true:)
            * Why have a ground cable there anyway? Vcc or some other signal would work as good (another signal might mean even less ringing compared to Vcc/GND, so why not cut straight to the next diff-pair, leaving something in between out anyway?). I mean, having the least components possible seems to be something of the big design goal in the cheap stuff you buy from china.

            (The point I’m trying to make is that GND is not “void” here, it is something that carries a current – probably one that’s changing (DC + AC component). I think the tricky part here is thinking that GND has DC-characteristics (voltage), but it really has AC-characteristics (current), since current, not voltage, is what will induce an electromagnetic field.)

          • pcf11 says:

            You need to tell my stepper motor drivers that DC currents don’t cause electromagnetic interference because I don’t think they got that memo.

          • tekkieneet says:

            >Vcc or some other signal would work as good

            Only if they are connected to the VIO of both the PCIe drivers/receivers
            on opposite side of the connector as any imbalanced currents of the diff
            pair would flow through them. Since this is not a practical thing to do,
            ground is preferred.

          • Joel Severin says:

            pcf11: Bring them here and I’ll see what I can do *fetches the large testa coil*.

            tekkieneet: Good point, but why not leave it out and have a smaller cable with fewer “inner” cables?

  2. TacticalNinja says:

    Holy shit.

  3. Elias says:

    That. is. f*cking. gorgeus!

    • meh says:

      Except, not really. Sloppy super long hoses everywhere with the clamps, pumps mounted not even at the same height and with crooked hoses, barber-stop like reservoirs that don’t fit the whole look, fugly wiring behind the panel, ugly yellow gauges at the bottom right that just don’t fit in, etc.

      I’ve seen far better “case mods” (like some on million dollar pc) and those didn’t really belong in a museum either.

  4. Jack says:

    Looks Excellent.
    I can’t help but laugh that he thought for even a second that the cheap risers were going to work in a daisy chain. I mean, really?

    Maybe HackaDay needs to run a series of articles outlining the basics of high-frequency circuits theory.

    • tekkieneet says:

      There are websites/mailing lists that address specifically about high
      speed signal integrity for people with the necessary backgrounds.

      Even within the community, there are different schools of thought of
      doing thing. Worst part is not followed everything to the letter and
      mixing them up.

      IMHO it is not a subject to be dumbed down for the general HaD hacking
      community. General rules of thumbs are bad as they tell you the HOW, but
      not WHY and WHEN the rules apply (and not apply).

      • Alex says:

        It can be boiled down somewhat. Obviously a complete understanding requires a lot more knowledge than the average hobbyist will have, but there is a lot you can learn that isn’t so complex. Henry Ott Consulting has a “tech tips” section of their website that is a very good introduction to these concepts: http://www.hottconsultants.com/tips.html

        • tekkieneet says:

          My beef with the “rules of thumb” approach over time people develope a
          superstition when they do hardware designs without knowing the WHY and
          WHEN.

          I have seen that at some places. Over time that has done more harm than
          good because it suppresses thinking out of the box and innovations which
          are what drives technology.

          Might want to visit Dr. Howard Johnson’s website: signalintegrity.com
          if you are interested in the subject.

    • mojojoe says:

      I hope HaD doesn’t start doing articles outlining theories, I like looking at pictures of actual stuff.

  5. Rob says:

    absolutely beautiful… wow, wow, wow. I’m stunned.

  6. But wheres the flux capacitor?

    And what are those barbershop lights?!

  7. Someone says:

    May the dust be with you !

  8. echodelta says:

    Why hide the busses and power and expose all that plumbing? It’s a computer not Kenner’s Hydrodynamic Building set. It looks like a model of some nightmare chemical processing plant, with pipes runing off to a river.

  9. AndroidCat says:

    I haven’t got enough room for a system like that. Maybe I’ll stick my Raspberry Pi up on the wall.

    • Exit151 says:

      LoL, indeed :) If it’s in a sunny place, you could even mount a solar panel on top – Like fancy art museums and private collections do with lights – To power it :) Add a wifi dongle and you’ve got a fully accessible computer on the wall with 0 wires :)

  10. asheets says:

    I like. I built something similar (but not nearly as good looking) for the IT department display case at the tech college I used to teach at. It was complete with a monitor and ran a .ppt presentation describing each part and its interaction with the whole of the system.

    The only thing my system had that this one doesn’t is the clear plastic cover that allows you to see the spinning hard drive platters and tone arm. But if this is actually a usable system, you probably wouldn’t want to risk it.

  11. Exit151 says:

    All that just for some litecoin mining :)
    Hehe, I jest! Seriously, not only is it stunning in terms of quality, it’s a pretty awesome rig in general aside of the “case” :) Nice job!

  12. Chris C. says:

    That sure is pretty. The barbershop poles looks a bit out of place in my opinion, though.

  13. Kris Lee says:

    I think it belongs to the Charley’s chocolate factory.

  14. Txbeard says:

    Absolutely Awesome. My hats off, and kudos sir on an awe inspiring project.
    Very nicely done

  15. matt says:

    It looks pretty and is nicer than my PC, but is this really that much of a hack? He assembled a PC and mounted it to some hardboard and acrylic.

  16. john says:

    to make applying the sticker less difficult, use an air-hockey table with the fan reversed, making it suck. put the sticker sticky side up, then lower the panel on it. easy for me to say not experiencing it, but that’s an approach i’d suggest.

    this build is fantastic! well done!

  17. Jim Turner says:

    case mods are not hacks.

  18. pcf11 says:

    First off to all of the naysayers yes, it is a hack. It isn’t my thing but I appreciate the craftsmanship. It is a great job.

  19. steven-x says:

    I once built something like this with a IBM XT motherboard, as I wanted a demo computer for a computer repair class I taught. But it sure didn’t look this good!

  20. Shobai says:

    Forgive me if i’m blind, but where’s this second GPU? I can see only one set of extenders (and I wonder about latencies, let alone noise) besides no visible second card…

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