At the beginning of 2007 AMD unexpectedly announced the intention to develop a new, open motherboard and chassis form factor, entitled DTX (because CTX was a monitor company?).

The idea behind DTX was to finally standardize small form factors for use by white box PC builders and the enthusiast community, both areas where BTX has not been able to really penetrate.

While Intel's BTX spec has been well implemented by the major OEMs, a quick search on Newegg reveals ATX/BTX compliant towers and two motherboards, both from Intel. We simply don't build BTX systems, which is unfortunate because it means that there's no real standardization in use for small form factor PCs by enthusiasts.

AMD also views BTX as too large of a departure from ATX for motherboard and chassis makers to justify bringing BTX boards to the enthusiast community. In AMD's eyes, BTX was a solution for a problem that no longer exists: the power-hungry Pentium 4. Thus DTX was designed as an auxiliary form factor standard, fulfilling the need for a small form factor standard that'll actually be used by more than OEMs.

What is DTX?

In February 2007 AMD published the DTX spec, the 10 page mechanical interface specification is unusually small for a brand new form factor, but it quickly makes sense when you realize that much of DTX is built off of ATX.

The DTX spec has four major requirements:

1) Motherboard size
2) Mounting hole locations
3) Rear I/O dimensions/locations
4) Expansion slot connector locations

There are two DTX form factors outlined in the spec: DTX and mini-DTX, both designed to augment, not replace, ATX.

DTX motherboards will measure 9.60" x 8.00" (243.84 mm x 203.20 mm), while mini-DTX boards measure 6.70" x 8.00" (170.18 mm x 203.20 mm). Mini-ITX motherboards can also be used in DTX compliant cases.

The big selling point for DTX is that it uses ATX mounting hole locations, so DTX motherboards can be used in current ATX cases.

DTX motherboards can have a maximum of two slots, either PCI Express or regular PCI can be used. The I/O connector plane is identical to what's used in current ATX motherboards, although the layout can obviously differ from board to board. The DTX spec doesn't govern what type of ports must be used, leaving it up to the motherboard makers' discretion.

There are no new power supply requirements for DTX, it simply requires the same 24-pin power connector and 2x2 +12V connectors supported by the current ATX specification. Cooling requirements remain unchanged as well, DTX systems can use standard heatsink/fan units.

All in all, the DTX spec is really about motherboard size, thus we've got a very simple spec to deal with. It truly is an augmentation to ATX rather than a replacement.

Differences between BTX and DTX
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  • kyp275 - Monday, October 22, 2007 - link

    In that case, I do agree with you. Miniaturization will happen, but unless there's a large market demand for it, it's not going to happen fast.

    and ultimately price is a big factor, and that's where the chicken-or-egg lies: price won't come down until there's a wide adaptation of the standard, but said adaptation won't happen 'til the price comes down.

    IMO in this particular case it requires a whole lot of manufacturers taking the plunge together across multiple devices and standards, and I don't see that happening any time soon, if ever.
  • sprockkets - Tuesday, October 23, 2007 - link

    I'm looking forward to having the first SSD built on the motherboard, say 16GB for the OS. Making a diskless system will be way easier.
  • chrispyski - Monday, October 22, 2007 - link

    Yup, thats precisely where the problem with BTX & DTX lies. If your gonna do some heavy gaming and need upgradability, then you have to go with ATX or at least mATX. But if all you want to do is some word processing and web, then laptops become more prevalent for their small size.

    DTX will have some hills to climb, no doubt. But eventually this could become a very good HTPC platform.
  • themadmilkman - Monday, October 22, 2007 - link

    I was about to say the same thing. For a general use PC, ie email, web surfing, maybe the occasional flash-based game, a tiny PC like that makes perfect sense. But for people who jam 2 video cards, a sound card, RAID, etc., into a case space becomes a priority fast.
  • Bluestealth - Monday, October 22, 2007 - link

    Its it really necessary?
    There is also flexATX(Part of the mATX spec) which is almost as small as mini-DTX, and that isn't doing so great.

    I feel that AMD is trying to solve a problem that isn't there.

    Most of the users looking for smaller systems than pico-btx are businesses wanting to deploy terminals. For that use, mini-ITX is big enough.
  • sprockkets - Monday, October 22, 2007 - link

    Would have built a BTX system using a pico or whatever the small form factor board is. But, try looking for such a case. There are none, with only one motherboard from Intel.

    Had Intel not been an ass and flipped all the slots around, and had the same setup of the fan and the same arrangement of the processor and such exhaust through the back, more people may have liked it. All that hot air that comes out of that duct system of theirs just went into the case, only to be exhausted by the power supply.

    OEMs built systems around BTX because, "Well, it came out from Intel, and since they are the leader, we have to use it and market it as a feature." Then they said how it makes the system quieter. Hmmm..., OEMs had problems with this since when? They custom make all there stuff.

    In any case, for the prototype case, when you say there was a vent missing from the power supply, can you say where? In the picture covering the system, is that also where it intakes air? Can't see any holes for the CPU fan.

    Wonder if they should not have used a Shuttle XPC format instead of this one, still using a laptop cd drive to decrease size.

    Shame also too there are no laptop cd drives yet that use SATA.
  • madgegafford1 - Friday, July 8, 2016 - link

    Thoughtful writing . I was fascinated by the analysis ! Does someone know where my assistant could possibly grab a blank a form example to work with ?

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