Why are there so few case designs that use PIO boards?


Average Stuffer
Original poster
Mar 14, 2019
PIO boards like this one specifically. I would think having an angled PCI-e slot to forego the need for riser cables would be a net benefit for many & offer some interesting small form factor designs.

I imagine case designs would be laid out much like the Skyreach S4 Mini, but in using a PIO the layout looks a little more clean and there's a bit more space for airflow/cooler or cable placement.

What barriers are keeping PIO boards out of many case designers minds? (it is simply availability/region issues?)

Secondly, I have a question brought by ignorance on the matter of motherboards; assuming we are dealing with a PIO board, can RAM slots be moved closer to that PIO slot? In the case of the motherboard pictured below, could SO-DIMM slots be used instead & moved to the red circle? I would think this would provide more space for CPU cooling solutions, but perhaps I'm wrong.


Master of Cramming
Silver Supporter
May 18, 2016
Lack of availability is a big problem. You'd need to furnish the motherboards because these are only available from China. Second, there's no official standard, it's more or less a de facto standard but there's nothing you can really rely on. Finally the space savings is less than you'd think since the slot is not cut into the PCB like http://www.jetwaycomputer.com/NF592.html


Shrink Way Wielder
Jan 20, 2018
Just to answer your RAM slot placement question: if it is possible at all (which is unlikely given how sensitive RAM signals are to interference) placing the RAM slots there would require adding several more layers to the motherboard due to the RAM traces then running on top of the PCIe traces. That would dramatically increase the cost of the motherboard, for very little gain. Then again, they're adhering perfectly to Intel's keep-out zone - why do you need more space than that?


Airflow Optimizer
Bronze Supporter
Jan 27, 2017
I wish I could get my hands on one of these boards, specifically a 300-series from Asrock. I had hit up the Asrock guy here, and got stuck in an "ask your mother" email loop between some Asrock reps.

But the boards look great, even if the space savings are minimal.

Also, the RAM slots are usually to the side for routing concerns - 2 DDR4 channels require some serious lines going directly to the CPU, as does the PCIe, which won't run parallel with the RAM. So they give each a 'quadrant' on most systems. Power in one, RAM another, and PCIe a third.


Master of Cramming
Silver Supporter
May 18, 2016
These boards are on taobao, use superbuy as a proxy, it's relatively easy. (For someone on this forum, at least :) .)


SFF Guru
Feb 23, 2016
I would love to design a case around this type of board, but it comes to availability of the boards themselves to consumers. The case wouldn't sell very well due to this and therefore is not worth investing the required time into developing a commercial product based around them.