Sub ITX Gaming Rig Idea.

[Bieberfever]

Hey Guys,

I've been brewing an idea for a while and would like to vet it with the community here before I go spending the money to build it. With the upcoming NuC release, several models are coming with both a M.2 slot and a SATA slot, including the i7 model.

What I am thinking of doing is picking up this adapter:

And turning the M.2 into a x4 PCIe 3.0 slot. Given my research, this should allow for a 32 Gbps transfer rate which should allow me to use a high end graphics card (970/980) with minimal performance loss. The best test I've seen of this would be a Thunderbolt 2 port (20 gbps) on a MBP running a 780ti at 80-90% normal performance.

The other issue I'm having is figuring out how I'm going to run power in the unit. The NuC comes with a 65w/19V adapter while I'd undoubtably have to use a 12V PSU to power the graphics card. Anyone who has suggestions on how best to address this.

It is also worth noting that I have an i5 iris pro Brix and mPCIe EGPU setup to vet ideas on while I wait for the NuC 2.0 to be released.

Am I missing something here or is this a viable idea? Any constructive feedback would be greatly appreciated

 

[Screes]

The HDPlex power board will work with a 19v input and will give you a 12v output for pci-e connectors, that would probably be best. http://www.hd-plex.com/HDPLEX-250W-Hi-Fi-DC-ATX-Power-Supply-16V-24V-Wide-Range-Voltage-Input.html
It's 123x44mm.

Some of the Pico PSU's are wide input's that will take a 19v input. They are smaller, though not sure if they will output voltage if they aren't plugged into a 24pin motherboard power connector.

You could also just get a graphics card that doesn't need a pci-e power plug, like a GTX 750ti.

The MB is about 100mm squared, and the short graphics cards are right around 170mm deep. So your looking at around 70x100mm of space in front of the motherboard to work with for some sort of dc/dc power board if you want one. Might be able to squeeze the HDPlex in that space if you slide the graphics card away from the motherboard a little bit.

With that in mind, you could possibly get the size down to around 180x220x50mm, or 2 liters on the low end. ITX motherboards, while bigger, are either the same depth or less than graphics cards, so the graphics cards tend to be the size limiter for how small of a case you can make.

Also, you'll probably need a flex riser to attach the graphics card to the board.

 

[iFreilicht]

Interesting idea, but as Screes said, the GPU tends to be the limiting factor to volume. The HDPlex will get you power for the GPU, and you can probably place it in front of the the mainboard, but you'd then need to split the power cable to plug into both the NUC and the HDPlex, except you solder a wire onto the back of the power connector of the NUC board.
Also make sure that the NUC actually has 4 PCIe lanes on the M.2 port, not just 1 as most current boards do.

 

[Stevo_]

I doubt that M.2 interface is rated for much more than a few SSD cards in terms of power draw, certainly not 60W that a 750 Ti will draw. If using a 970 type card then 6/8 pin power would need to be the source of 12v. When splitting power, a single point ground before coming in is desirable rather than having initial connecting point of grounds thru the board, also probably want to disconnect 12v power pins from x4 connector on the interface. Could be a real smoke show if done badly.

There are powered PCIE estenders that might be worth looking into to make it work, gets rid of some of the PSU merging headaches.

EDIT: Something like this, will take ATX 24-pin power or Dell DA2 8-pin directly(and brings out an external 8 pin card power connector) limited to 1x PCIE though

http://www.bplus.com.tw/Adapter/PE4C%20V2.1.html

 

[Bieberfever]

Interesting idea, but as Screes said, the GPU tends to be the limiting factor to volume. The HDPlex will get you power for the GPU, and you can probably place it in front of the the mainboard, but you'd then need to split the power cable to plug into both the NUC and the HDPlex, except you solder a wire onto the back of the power connector of the NUC board.
Also make sure that the NUC actually has 4 PCIe lanes on the M.2 port, not just 1 as most current boards do.

Pretty sure most M.2 interfaces are either 2x or 4x (B or M keyed). Can you tell me where you got your information that most of them run at 1x? 2x and 4x would both likely be sufficient for the Galax 970 I'm planning on using, but probably not 1x. Cheers.

 

[iFreilicht]

Pretty sure most M.2 interfaces are either 2x or 4x (B or M keyed). Can you tell me where you got your information that most of them run at 1x? 2x and 4x would both likely be sufficient for the Galax 970 I'm planning on using, but probably not 1x. Cheers.

I was misinformed, it's 2x. M.2 doesn't even have keying for 1x

 

[kierwest]

I look forward to a full test. I reallly want to see how this performs considering how limiting the nuc cpu performance is.