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Q: How can I cram a DDR DIMM into 0.5" of vertical clearance? ( No Answer,   4 Comments )
Subject: How can I cram a DDR DIMM into 0.5" of vertical clearance?
Category: Computers
Asked by: megacz-ga
List Price: $100.00
Posted: 25 Dec 2002 11:30 PST
Expires: 24 Jan 2003 11:30 PST
Question ID: 133306
Abstract: I need a way to mount a PC motherboard with a single DDR
          DIMM slot in a space that has EXACTLY 0.5" clearance above
          the surface of the motherboard.  The only barrier is that
          the DIMM is much taller than this limit.

WARNING: Simply searching the web with google probably won't get you
         the answer to this question.  I'm a pretty darned good
         googler, and I couldn't come up with anything after two weeks
         of searching.  Your best bet is to either be a person who is
         knowledgeable about electronics or else ask a friend who is.
         Calling around (you know, on that telephone thing) also might
         help.  This is a $100 question, so I don't think that's

I'm trying to mount a mini-itx motherboard in a space that has only
0.5" of clearance above the top surface of the board.  We've come up
with some very creative solutions for reducing the height of all the
components of the motherboard *except* for the DDR DIMM.  This is
where we need help.

We are looking for a solution that doesn't involve resoldering 184
connectors.  We've found an appropriate angled socket (from Meritec)
and a manufacturer to perform the board modifications, but a simpler
solution (not involving outsourcing or special board-mounting tools)
would be VERY valuable to us.

Possible solution leads:

  - Find a supplier for a part that has a DDR DIMM card edge connected
    to a flexible ribbon cable connected to a DDR DIMM socket.

  - Find a supplier for a 90-degree DDR DIMM riser card that is less
    than 0.5" tall.  Beware: an old DECStation used these, and they're
    still available, but they're 184-pin proprietary DIMM connectors,
    not DDR DIMM connectors (the voltage key is in the wrong place).

  - Something more creative that I haven't thought of.

If nobody successfully answers the question, I will offer $25 for
information which leads me to the solution (for example, the name of a
good consultant I can pay to devise a solution).  This also will be
paid via paypal, and you'll have to trust me.  Such information should
be posted as a comment.

Everything above here is just background; the official question
statement follows.  Your answer MUST meet these criteria in order to
be accepted:

  "Find a way to connect a 1.2 inch tall 184-pin DDR DIMM to a VIA
   EPIA M9000 motherboard in such a way that the DIMM does not
   protrude more than 0.5" above the top surface of the board.  The
   solution must not involve any expensive tools (anything over $400),
   any custom outsourced manufacturing, or soldering more than 20
   connections.  The solution MUST cost less than $100, and it would
   be preferable if it were under $50.  The solution must not require
   more than 30 minutes of manufacturing time once all parts have been
   received.  You may choose to use a shorter DIMM (such as 1.0 inch
   low-profile), however these are more expensive -- the difference in
   cost will be subtracted from the allowable total cost.  If volume
   discounts are required to meet the price limit, you may assume a
   quantity of 100 units."

Stuff I've come across in my searches:

   - Here are the specs for the board we're using:

   - Here's a 0.75" tall DDR DIMM; unfortunately the cheapest one is $110
     in large quantities, and 0.75" is still too tall.  I don't think there's
     anything shorter out there:

Merry Christmas and good luck!!!

  - Adam

Request for Question Clarification by arimathea-ga on 26 Dec 2002 06:34 PST

Is your board in a Cubid case, or similar?

Clarification of Question by megacz-ga on 26 Dec 2002 06:44 PST
Yes, it is in a Cubid/Morex 2688, however we have heavily modified both the
case and board, and we're putting extra components above the motherboard
(hence the 0.5" clearance).

Request for Question Clarification by arimathea-ga on 26 Dec 2002 06:49 PST
0.77" is too big, as you say.  I found an 0.72".  What is the exact
height this solution needs to be?

Clarification of Question by megacz-ga on 26 Dec 2002 07:13 PST
Unfortunately it's exactly 0.5" of headroom.  0.72" will be too much.

Request for Question Clarification by arimathea-ga on 26 Dec 2002 07:20 PST
But how much is the socket height itself?  My thought is that once you
put the memory in the socket you will reduce the height slightly.  The
question is, how much does that height need to be reduced.

I'm not having much luck finding solutions.  I did find some riser
cards that have angled sockets, but they still clock out at ~0.70".

I've called around a little bit to some engineering friends and
they're leaning towards the same solution you are.

Some BIOS support change in the voltage key position for the DIMMs. 
You may also want to try the folks over at Molex; they often have
unpublished solutions for these problems.

Good luck!


Clarification of Question by megacz-ga on 26 Dec 2002 11:10 PST
It is my understanding that memory sold as "X inches high" is X inches high
when installed in the socket.  I've verified this by measuring myself on some
1.0" DIMMs I have.  Even if this isn't the case, you can assume that it is.
We can probably squeeze out another 0.05" if we need to by shaving the plastics
on some of our components.

It sounds like you've found a lot more information than I have, and it would
be useful to us even if it doesn't solve our immediate problem.  Let's wait
one week; if nobody else answers the question, you can post your info for
where to find a 0.70" DIMM riser and I'll accept it as an answer.  But like
I said, please wait one week in case somebody else has a complete answer.
I'll email you in a week to remind you.


Request for Question Clarification by duncan2-ga on 26 Dec 2002 12:07 PST
Hmm, I've worked on this for a little bit, and haven't found much.  I
agree that you probably won't find a DIMM much shorter than 0.77” 
(The smallest I found while searching were the ATP DIMMs you

So that leaves either an angled socket & resoldering, (I found the
Meritec adapters too), or some sort of cable/socket adapter.  So far
though, I haven't found an adapter small enough to fit your

Have you considered having a custom adapter manufactured?  Perhaps
from a company such as Adex Electronics?  Their FAQ suggests a willingness
to do custom bus adapter manufacturing, and their product line already
includes 184-pin DIMM risers:
(They also seem to have one right-angle adapter option for an extra
tall 100-pin DIMM riser, so it seems conceivable that they might be
willing to do right-angle adapters for shorter, 184-pin sockets.)


Clarification of Question by megacz-ga on 26 Dec 2002 12:21 PST
I've actually already emailed Adex... they said they'd never heard
of a right-angle DIMM connector.  I didn't inquire about them designing
a custom-built one.

We have considered custom manufacturing; in fact, that's our back-up
plan.  If we can't figure out a way to do it without custom manufacturing,
we'll order the boards from VIA without the DIMM socket (they can do that)
and have Laco (our contract manufacturer) solder on the Meritec 90-degree

My goal with this question was to see if we could find a way to pull this
off without custom manufacturing.

Clarification of Question by megacz-ga on 26 Dec 2002 12:22 PST
Er, that should be "DIMM riser", not "DIMM connector".  There are plenty
of 90-degree DIMM connectors out there.

Clarification of Question by megacz-ga on 28 Dec 2002 22:01 PST
Attention arimathea-ga:

It looks like nobody's going to post any more info.  If you have information
which matches the question, except that it's 0.7 instead of 0.5, but otherwise
meets all the requirements, please post it and I will accept it as the answer.


Request for Question Clarification by arimathea-ga on 05 Jan 2003 12:42 PST

Sorry, I didn't get this request until today.

My solution was also Adex, so it looks like we're out of options.

My apologies.

There is no answer at this time.

Subject: Re: How can I cram a DDR DIMM into 0.5" of vertical clearance?
From: georgeioak-ga on 03 Jan 2003 20:45 PST
How much memory are you looking to have in this system? Timings on the
DDR bus are fairly tight so even if you found an adapter board I'd be
careful of getting reliable results. I worked for NEC for many years
on our memory modules (both custom and standard) and I'd say your best
best is to use the 90 degree connectors but then your height is 0.555
(at least with the connectors I checked). If you go with the 25 degree
socket you'll need a module of 0.73" tall to meet your height
requirement. To get yourself a little extra headroom you can chamfer
the memory module PCB edge. JEDEC standard is a 3.0mm keepout around
the module but the low profile modules might not adhear to this rule.

If you are really hard up you try to cut the bottom of the memory
module at the gold contact pads but that gets a little more invloved
and very likely you'll pull up the pads rather than cutting cleanly
through them. Not to mention the contact point in the socket might not
hit the pad anymore.

I'm very curious of your overall design though. If you only have 0.5"
above the MB how are you going to cool it?

Subject: Re: How can I cram a DDR DIMM into 0.5" of vertical clearance?
From: megacz-ga on 03 Jan 2003 23:03 PST
> How much memory are you looking to have in this system?

As little as possible (probably 64MB)

> If you only have 0.5" above the MB how are you going to cool it?

We use the VIA EPIA Eden chip, which does not require a fan.  On top
of it we put a solid-state thermoelectric cooler and a broad copper

Our goal is to have a fanless (silent) machine.
Subject: Re: How can I cram a DDR DIMM into 0.5" of vertical clearance?
From: megacz-ga on 04 Jan 2003 20:54 PST
> 200-pin SO-DIMMs should not cost you more that the 184-pin DIMMs
> (although people try to sell them for more). You should be able to
> create this "adapter PCB" quite easily and have the PCB manufactured
> for a few dollars each. I would say this solution should run you no
> more $25 extra per system even amortizing in the design work for the
> adpater board and extra manufacturing on the MB.

Can you refer me to a company that would be able to manufacture it so that
I can confirm this and get a quote?

Subject: Re: How can I cram a DDR DIMM into 0.5" of vertical clearance?
From: joshcramer-ga on 30 Apr 2004 15:18 PDT
I believe this will do the trick with some low profile memory:

You'll need to unsolder the existing DIM socket and replace it with this one.

Good luck!

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