[MinnowBoard] Minnowboard and a standard Nvidia GPU?

[Scott Guthrie]

You know...this type of thing has been tickling my brain lately.  I wasn't
thinking Minnowboard though...but a NUC (i7 or i5) would seem to have
enough oomph to do this.  Sadly they seem to be limited to 12 PCIe lanes
and 4x1 or 2x4 lane configurations.

And frankly, I can surmise this isn't really in the INTEL roadmap (after
all a NUC is not really MEANT to be a Gaming PC), but damn, one x16 Slot,
even if I had to through a slot extender to a second case and power the GPU
separately.

Once can dream I suppose.

Sorry....Tangent.

S.



On Wed, Jul 15, 2015 at 8:04 PM, John 'Warthog9' Hawley <
warthog9 at eaglescrag.net> wrote:

> On 07/15/2015 08:42 AM, Ashot Arshakyan wrote:
> > Hello. I have a project where I need to render thousands of OpenGL
> > frames each second by using a x86 based PC and a typical high end NVidia
> > GPU.
> > The problem is I have a pretty limited space for the electronics of the
> > device I'm working on so I was hoping I could use a single board PC
> > instead of using a mini ATX.
> > SInce the main rendering job is done on the GPU, I thought the
> > Minnowboard CPU would be fast enough for the job. What are your thoughts?
> > Now I just need to know how I can connect a standard GPU to Minnowboard.
> > I'm thinking of powering the GPU with a flat 12V 30A power supply
> > instead of ATX to again save some space.
>
> So there's a couple of things you should be aware of while pondering
> this.  It *MIGHT* work, but you'll need to consider that modern graphics
> cards use a LOT of bandwidth for moving data in and out of the graphics
> card.  They usually employee 16 lanes of PCI-e, which at it's oldest and
> slowest is about 4GByte/s.  So there's two potential issues here:
>         1) The MinnowBoard only has a single lane of PCI-e v2
>            available for use through the high speed expansion
>            header.  This gives you a maximum throughput of
>            about 500MByte/s
>
>         2) *MANY* graphics cards won't negotiate their PCI-e
>            lanes down to the point where it will work in a x1
>            connector.  This is mostly an assumption from the
>            manufacturers that the card would never be used in
>            such a slot.  Case in point when we tried to get a,
>            admittedly rather high end, graphics card working on
>            the MAX on April 1st this year, it didn't work as
>            the card couldn't negotiate down to a single PCI-e
>            lane
>
> The only way to overcome 2, that I can think of, is to put a PCI-e
> switch on the bus that can provide 16 lanes, but only upstream via 1.
> This still limits your maximum bandwidth to 500MByte/s though, but it
> should get you past the lane negotiation issue.  That's a substantial
> amount of work though, and likely a need for a custom lure to be built
> to accommodate it.  Just some thoughts.
>
> - John 'Warthog9' Hawley
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