Examining BTX cont'd

The D915GMH is essentially a microBTX version of our D915GUX motherboard with a few functional differences on top of the obvious BTX design. When we first laid eyes on the D915GMH the first thing we noticed was the arrangement of the CPU socket, Northbridge, and Southbridge. The CPU socket is placed at the front of the motherboard with the Northbridge behind it slightly to the left and the Southbridge behind the Northbridge directly in line with the CPU socket. Each is positioned on a diagonal which we assume will improve air flow around all three chips. Since these components are three of the hottest running components in a PC it made sense to position them in line from front to back and we expect fans to be placed in that same linear arrangement.

A design that revolves so much around irregularly placed components was slightly unusual for us to see.  Although software dictates the exact routing of all the traces from component to component, its very obvious that some very complicated math went into assuring each bridge and component was placed correctly.  The fact that almost nothing seems to be at a right angle is a little overwhelming at first.

The IDE and Floppy ribbon headers were separated on the board. We found this to be inefficient, especially for the floppy drive, since they are on opposite sides of the system. Though not as important nowadays since SATA drives are moving into mainstream PCs, those who would like to use floppy drives are left with only the option of using a lengthy rounded cable. Since the AOpen/Intel combination we received today looks more like an OEM design than something we would typically buy and assemble from NewEgg, problems with the floppy cable placement shouldn't be a huge issue.  


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There are 4 DDR memory sockets which are placed at the far left edge of the board. Keep in mind our D915GMH runs on DDR2, but other than design layout that is the only major difference between our microATX and microBTX motherboards.


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The PCIe x16 slot is positioned about 3 inches from the rightmost edge of the D915GMH. Since the AOpen B300 is a half height case a riser card is included for the PCIe x16 slot. This allows the VGA card to be mounted towards the center of the motherboard to keep it inline with the CPU and chipset.

Examining BTX BTX Cooling and Airflow
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  • ThelvynD - Monday, November 15, 2004 - link

    We've been getting in new HP 7100s here at my work center and they've been in the micro-BTX format. I don't any major problems with it so far. Pic below.

    http://www.picsplace.to/044712/HP-BTX.JPG
  • Nonsense - Monday, November 15, 2004 - link

    #36 - Thanks Purav.
    Can you tell me - is the PS blowing in or out, and is the CPU fan blowing in or out? I'm still trying to figure where all the air is comming from.
  • PuravSanghani - Monday, November 15, 2004 - link

    #34: If you look at the picture of the backside of the B300 on page 8 there are groups of holes above the VGA expansion slot as well as to the right between the expansion slot and the power supply. There are also holes lining the bottom of the case if you look closely. We were surprised ourselves to find how well passively cooling all of the components in a system would actually work. And from the pictures you can also see there aren't too many holes for a large amount of air to come in through!
  • PuravSanghani - Monday, November 15, 2004 - link

    #25: Actually, the front panel connectors *are* standardized and combined into one single plug. We mentioned this on page 8 of the article, "First Look: AOpen B300 BTX case cont'd", in the paragraph where we talk about the auxiliary module.
  • Nonsense - Monday, November 15, 2004 - link

    #28 - I don't understand the air flow.
    If the CPU fan is blowing out the front of the case, then the PS _must_ be blowing in.
    Blowing hot air into a case does not sound good. Is that how it works?

    If the PS is also blowing out, then you have a vacuum. I do not see any heat comming into the case from the PS, so it must be blowing out...?!

    Where is the air comming from that is cooling the graphics card? It looks like mostly dead air in that corner - there are only tiny grills on the back.
  • Sunbird - Monday, November 15, 2004 - link

    From last paragraph of article:

    "The ATX case used more space and ran louder."

    Space is not evil!, its a good thing for when your drop a small screw, or have hands that fit your 6'6" frame. And loudness can be adressed in other just as succesfull ways.

    "Don't forget that additional non-redundant fans increase the failure rate of a computer as well - more moving parts."

    And what if the single fan on the BTX sollution fails? That is really non-reduntant if you ask me, anyone agree?

  • Sunbird - Monday, November 15, 2004 - link

    #20, I agree, I have a Packard Bell P1 133MHz flat desktop case PC in my workshop and that is almost exactly the same design as this, except the stuff like the optical drive, hard drives and power supply was swapped from the right to the left side of the case, othewise its exactly the same. Glad to see some oldschool designs again, lol

    #27's idea is brilliant, they quickly implemented something like that with the cases and their front USB options, those LED and power button connector have been around much longer. What's taking them so long?
  • epiv - Monday, November 15, 2004 - link

  • skunkbuster - Monday, November 15, 2004 - link

    flash in the pants?
  • Zebo - Monday, November 15, 2004 - link

    This is going nowhere quick. It's obvious Intel will no longer need it when they make the Dothan desktop transition plus AMD all case and PS manufactures hate the idea. Just wahtever you do don't go buying an $300 Lian Li and $120 PSU since BTX is a flash in the pants.

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