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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  • defter - Monday, October 22, 2007 - link

    quote:

    but these days even 2.5 hard drives can reach extremely high speeds and capacities.


    Where I can find 500GB 2.5" HDD for $100?

    For most of the people size isn't that important and they do not want to pay extra for a small size.
    Reply
  • Calin - Monday, October 22, 2007 - link

    Forget about price, where can I find a 2.5" hard drive at 750GB?
    Also, with a dual slot cooled graphic card, you are out of luck for SLI on a micro ATX board
    Reply
  • Myrandex - Monday, October 22, 2007 - link

    100% Liar Face detected.

    http://www.theinquirer.net/en/inquirer/news/2006/0...">http://www.theinquirer.net/en/inquirer/...6/03/13/...

    I have that board, and it is awesome. It is keeping me from upgrading as I have never found a mATX board as good as that one for either AM2+ or Core2/4/1024 Duo chips.

    I actually wish someone would make that with a socket AM2+ socket on there so that I could take the same board with the same Chipset and be Phenom ready (or someone make a Intel CPU compatible version plz!)
    Reply
  • themadmilkman - Monday, October 22, 2007 - link

    Okay, then show us an mATX board that allows you to run at 16x in SLI using double-slot cards, because that one does not. According to the article you linked, they only run at 8x when using the outer slots. Reply
  • sprockkets - Tuesday, October 23, 2007 - link

    yeah, but I dare you to show the improvement over 8x.

    Gamer systems have to be ATX. The video cards are huge, and besides, it is all about show, i.e. windows, lights, UV, aluminum, etc.
    Reply
  • kyp275 - Monday, October 22, 2007 - link

    Not quite, it all depends on what you're using your PC for.

    For many moderate to power users, cooling is a big issue, and when you stick all that power-hungry CPU/GPUs into a small case, effective cooling becomes extremely difficult to achieve.

    I'm currently running a e6600 with a single 8800gts card in a P182 case, a full size mid-tower, and it's barely big enough to fit all the components, their cooler, leave room for optimal airflow, and I'm not even running SLI or crossfire. There's a reason why you don't see any high-end machines in small-form factors, they simply don't work with today's cooling methods.

    Price is also another issue. While your right that not being the standard has to do with the price premiums, there are also physical limitations that goes into smaller parts such as a hard drive. There's simply less physical area in the 2.5" drives to store information compared to their 3.5" counterpart, and unless you can come up with a way to defy the law of physics, that's just the way it's going to be.
    Reply
  • BansheeX - Monday, October 22, 2007 - link

    Don't you see the fallacy in that viewpoint, though? In five years, you'll be saying 2TB on a 2.5 isn't enough when you can get 4TB on a 3.5. And if we had double-ATX sized computers as a standard, you'd be having the same grievances about the ATX standard. "Oh no, I can't use octo-SLI or a 1500w power supply! Noooooo!" The heat and cost issues people are bringing up have everything to do with the fact that costs are lower insatiable appetite for power. Multiple-video cards is a joke and always has been. The industry standard shouldn't be ATX with smaller form factors labeled as for the "enthusiast HTPC crowd." Micro-ATX should be the standard with ATX being the less common "enthusiast" platform for people who are insatiable enough to buy into SLI. Reply
  • kyp275 - Monday, October 22, 2007 - link

    quote:

    In five years, you'll be saying 2TB on a 2.5 isn't enough when you can get 4TB on a 3.5.


    If in 5 years i say that 2TB on a 2.5" isn't enough, it'll be because it ISN'T enough for my usage. It wasn't that long ago when 160gb or 320gb was more than enough for me, but the increasing size of many media files (lossless audio, HD vid, larger games etc.) means that those sizes are no longer enough, at least for my need. And as long as 2.5" drives continue to be more expensive and slower than their 3.5" counterpart, people will prefer the 3.5" drives.

    Unless you want to pay for mine, that is :P

    quote:

    if we had double-ATX sized computers as a standard, you'd be having the same grievances about the ATX standard. "Oh no, I can't use octo-SLI or a 1500w power supply! Noooooo!


    It's the softwares that dictates what hardwares we use, I'd imagine most people don't choose what hardwares to use for the sake of the hardwares, except maybe the bench-mark enthusiast crowd.

    Basically, your arguments are ignoring too many things. People will not get "octo-SLI" or a 1500w PSU unless there's a need, real or perceived, being driven by their particular application. As for heat issues, that's purely the product of the way our technology works today. If you have a problem with that, take it up with the laws of thermodynamic.

    quote:

    The industry standard shouldn't be ATX with smaller form factors labeled as for the "enthusiast HTPC crowd." Micro-ATX should be the standard with ATX being the less common "enthusiast" platform for people who are insatiable enough to buy into SLI.


    and why is that? give me a reason why small form factors should be the standard. ATX isn't just for people who want to have SLI, like I said in a post earlier, I'm running a single 8800gts in a full size mid-tower, and it's just barely enough. There's simply no way to jam all the stuff I have in that PC into a SMF box without the stuff overheating all the time.

    and that's assuming I can even jam all that stuff in there in the first place.
    Reply
  • bupkus - Monday, October 22, 2007 - link

    quote:

    give me a reason why small form factors should be the standard.

    45nm--->32nm, etc.

    I don't thing BansheeX is suggesting that you be forced to cram your high powered system into a tiny case. I think that market trends to miniaturization for all and especially for the bulk of users is inevitable.
    Reply
  • BansheeX - Monday, October 22, 2007 - link

    Exactly. All I'm trying to get across here is that when 95% of the market would find matx computers with current capacity 2.5 HDs totally sufficient, staying with ATX as the industry standard just seems foolish. Look at all of the things that have changed to allow for this. Floppies are dead. Onboard ethernet is now good and standard, freeing up a slot that always used to be taken. Onboard audio got better, making sound cards unnecessary for most. 2.5 HDs got massive and storage density and 8mb cache increased their speeds dramatically even at 5400rpm. That and they barely get warm to the touch and they make virtually no sound, in turn making them more reliable. It's a serious improvement that will only continue to get better and cheaper if 3.5 gets canned. I honestly believe that 3.5 hard drives are an unnecessary dinosaur format. Macs and consoles are 100% correct to choose 2.5 while people who only think about size/cost continue to perpetuate 3.5's just as they would an even cheaper, larger, noisier and more power-hungry 5" HD if one existed.

    So yes, it's positively peculiar to me that we continue to see things like 5-expansion ATX persist as the norm while smaller boards are relegated for niche markets. I can't believe how resistant the PC market is to change. Christ, I still have parallel and serial ports on the back of my new motherboard. Fifteen years later... WHY ARE THESE HERE. I don't care how many people bitch and moan, the industry needs to grow some balls like they did with SATA.
    Reply

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