[MinnowBoard] 4GB Ram need pcb rerouting?

[John Hawley]

Inline -JH

On 06/16/2016 04:06 AM, Joe Tom Collins wrote:
> I think this this thread alone should tell the MinnowBoard designers
> there is a market for a board where the user has more choice for RAM.
> 
> Personally, if it's possible, I would like to see some way to add a
> couple of SO-DIMM's for up to 32GB.

So the reason SODIMMs weren't used boils down to 2 things:

1) Cost
2) Size of the board

To the first point, we are trying to keep the board within a certain
price range, and a lot of that has to deal with what we learned out of
the old V1 (the old square board), and partly just based on what's
available in the market and price ranges.  Folks are very cost
sensitive, and we are trying to keep that in mind with the design
decisions we've made.

To the second adding the connectors would push the size of the board up,
at least, into the size of the old v1 if not actually closer to a
mini-ITX.  We generally felt that doing that making a board that was too
big.

Now to the ram size, with the Baytrail's - we aren't getting to 32G of
RAM, and in fact we'd have to go up into the Atom server chips to get
close to that.

http://ark.intel.com/products/78477/Intel-Atom-Processor-E3826-1M-Cache-1_46-GHz

http://ark.intel.com/products/78475/Intel-Atom-Processor-E3845-2M-Cache-1_91-GHz?q=e3845

Max out at 8G officially supported, kicking up into the Atom server
chips would make the board a lot more power hungry, a lot bigger, and a
LOT more expensive of a board.

> I realize the processor might not be capable of that, but my retro PC
> history has me gun shy about any system that can't at least take the
> full amount of RAM that the processor takes. No matter what, it always
> ends up being an issue.

Depends on specific use cases, but yes.  We made specific design
decisions, that may, or may not, work out for your use cases.  There are
things in the works, like the board that B-O was talking about that they
are working on, where the full amount of RAM is available.  Right now
there's the Turbot and the MAX that are available, that's not to say
that more boards won't be available with other options - that's why this
is an Open Source Hardware platform, so folks can modify it as they need.

> Or how about some high speed SD RAM if power consumption is an issue.
> Maybe 2GB of SD RAM that can run as main memory, or also as a cache for
> an SO-DDR3 DRAM hood that can take as much RAM as the processor could
> handle.

Are you talking more like onboard eMMC?  Right now the best we can do is
mSATA via something like the Silverjaw, or even an nvme based storage
off of mPCI-E via the same.  I know that adding eMMC has been something
we've discussed a lot, and I know some folks are already working to add
(like B-O)


- John