GPU Thin Mini-ITX with discrete graphics card

[Sean Crees]

Got the information from Asrock who directlt asked their board designer ... Guess this is just the safest source.

But if you wanna play with fire ....

I've seen first hand people do things on this forum that void warranties and are likely not recommended by manufacturers all the time. The motherboard manufacturer is required per pci-e to have all those power pins connected. So the same power connectors are on that x4 connector as they would be for an x16 connector.

It's the same effect as wiring up an external power brick, pulling 17amps over an 18 gauge wire, even though an 18 gauge wire is only "rated" for 16 amps. Will it work, sure; is it recommended, no. It will heat up more than it should, and if not adequately cooled has the possibility of melting the wire. That's assuming the motherboard manufacturer doesn't just use the same width traces for all its pci-e connectors regardless of which physical slot it used.

 

[jeshikat]

The power has to be negotiated between the card and the motherboard. Normally only x16 cards are allowed to negotiate the full 75W.

So a board with only a x4 slot is probably only specced for 25W.

 

[GuilleAcoustic]

I'd say that people do wathever they want with their hardware, could it be voiding warranty and frying it.

But I can't advise someone to do something I know being risky and out of spec when he/she asks for advise. It might work but it might also not work and just fry everything after a few weeks.

 

[iFreilicht]

Got the information from Asrock who directlt asked their board designer ... Guess this is just the safest source.

Yeah well ASRock also said that the X99-ITX requires -12V and Aibo proved them wrong on that.

But everyone is correct here. The PCIe slot itself is physically able to transfer 75W even over a 4x connection, but in practise the current will be limited by the negotiation between board and GPU and by the power regulators on the ITX boards, the latter of which are not specced for 75W on the PCIe bus. Even the CPU power draw is very limited, 50W headroom aren't really there, so even if you managed to trick the board into not shutting down because it detects too high current on the PCIe slot, you're likely to burn the regulator circuitry.

 

[Ceros_X]

Pretty sure @QinX vaporized a trace when he was doing his thin ITX with discrete GPU build

 

[QinX]

Pretty sure @QinX vaporized a trace when he was doing his thin ITX with discrete GPU build

That was at my own fault and not the motherboard.

I thought I had removed all 12V traces from my riser, but 1 sneaked in and it wasn't a power trace but a signal trace in terms of width. Now try pulling 25W or 75W for that matter through a single strand of copper. Yeah

As @iFreilicht says it is important to take into account the power regulation of a Thin ITX motherboard
The boards are made for certain hardware. The board has to convert 19V to 12V for the CPU and GPU. They won't engineer a board that can handle a 75W PCIe card and a 90W CPU. But a 65W TDP CPU and a 25W PCIe card.

 

[CXH4]

That was at my own fault and not the motherboard.

I thought I had removed all 12V traces from my riser, but 1 sneaked in and it wasn't a power trace but a signal trace in terms of width. Now try pulling 25W or 75W for that matter through a single strand of copper. Yeah

As @iFreilicht says it is important to take into account the power regulation of a Thin ITX motherboard
The boards are made for certain hardware. The board has to convert 19V to 12V for the CPU and GPU. They won't engineer a board that can handle a 75W PCIe card and a 90W CPU. But a 65W TDP CPU and a 25W PCIe card.

If I didn't want to vaporize or modify anything on the motherboard, would this riser card be safe to use?

Fixable PCI-E 16X to 1X Adapter USB3.0 USB 3.0 Riser Cable Flex Flexible Extension Cable w/ Molex 4 Pin Power Connector https://www.amazon.com/dp/B00IMYODGS/?tag=theminutiae-20

 

[Kmpkt]

That's not going to work because you'll lose a tremendous amount of bandwidth due to it being an x1 interface. A powered X4 to X4 or X4 to x16 would work. If the PCIe slot on your motherboard will allow over length PCIe cards to plug into it, then you can get a powered x16 to 16x riser which is much easier to find. If none of these work you can get a x4 to x16 riser board from Adexelec and put a powered x16 riser into that.

 

[CXH4]

That's not going to work because you'll lose a tremendous amount of bandwidth due to it being an x1 interface. A powered X4 to X4 or X4 to x16 would work. If the PCIe slot on your motherboard will allow over length PCIe cards to plug into it, then you can get a powered x16 to 16x riser which is much easier to find. If none of these work you can get a x4 to x16 riser board from Adexelec and put a powered x16 riser into that.

So something more like this correct?

PCIe 1x to 16x Powered Riser- Extension Cable & MOLEX Power- GPU Riser Extender Cable - Ethereum Mining ETH https://www.amazon.com/dp/B01NBC51KV/?tag=theminutiae-20

 

[EdZ]

So something more like this correct?

PCIe 1x to 16x Powered Riser- Extension Cable & MOLEX Power- GPU Riser Extender Cable - Ethereum Mining ETH https://www.amazon.com/dp/B01NBC51KV/?tag=theminutiae-20

No, that has the exact same problem as your first riser: only a 1x link.

 

[Kmpkt]

Try this:

https://www.moddiy.com/products/PCI...CurrencyId=4&gclid=CL7ZoP309tECFYhbfgodGSIOvQ

 

[CXH4]

So with that riser, a configuration like this one should work?

https://pcpartpicker.com/list/VL8Hr7

I would also have to find a 12v power brick for the motherboard though. Not necessarily the motherboard on that list. But 150 watts is usually the max amount that the motherboard can handle on its own correct?

 

[GuilleAcoustic]

Do you already have the thin-ITX motherboard ? If no, a regular ITX + pico PSU would be better I think.

Thin mini-ITX uses 19V PSU (+/-10%). The PCIe riser will need a 12V PSU though.

 

[CXH4]

Do you already have the thin-ITX motherboard ? If no, a regular ITX + pico PSU would be better I think.

Thin mini-ITX uses 19V PSU (+/-10%). The PCIe riser will need a 12V PSU though.

I have a mini-itx and 160XT, I don't have a thin-itx motherboard. I was considering making a build with a thin-itx as a project. I also saw that some of the thin-itx boards support 12v-19v which makes me believe that it may be possible to create something like this with not too much hassle.

 

[GuilleAcoustic]

I have a mini-itx and 160XT, I don't have a thin-itx motherboard. I was considering making a build with a thin-itx as a project. I also saw that some of the thin-itx boards support 12v-19v which makes me believe that it may be possible to create something like this with not too much hassle.

12V thin mini would be perfect indeed, haden't heard of them till now. I love my thin ITX, very interesting boards.

 

[aquelito]

If the PCIe slot on your motherboard will allow over length PCIe cards to plug into it, then you can get a powered x16 to 16x riser which is much easier to find.

The PCIe slot on my Asrock H110 Thin Mini-ITX is open ended and does accept 16X cards.

I asked Liheat if they will ever produce powered risers ; hope they will

 

[CC Ricers]

Ah I see there's still some interest in this. We would have to take Asrock's word for needing a powered riser. Now, I still have some powered riser parts left over from the GPU mining craze. One of them uses molex to drive the 75w of power from the 12v line and includes a USB 3.0 to PCIe x1 adapter.

It is possible to make a build in a super slim case, thin ITX and with a GPU that does not need a PEG connector. The powered riser is rather bulky, so I'd have to figure out how to make it fit in a small space.

The kicker here is to use a 200w mean well PSU to power it all. One 12v connection goes driectly to the molex in the powered riser, the rest to power the mobo and CPU. As there are thin ITX that have a 12v power header this could very well work.

 

[aquelito]

Only the Gigabyte motherboards allow 12V input fro mthe 4 Pin on-board connector.

They cost twice as much as the Asrock (85 vs 160 € in France).

 

[CXH4]

This is the motherboard that I'm interested in:

http://www.gigabyte.us/products/product-page.aspx?pid=5881#ov

It says it supports 12/19~24v, however, I don't know if that means through the power input it already has. Not only that, I don't know how much wattage it can run at continuously.

 

[iFreilicht]

This is the motherboard that I'm interested in:

http://www.gigabyte.us/products/product-page.aspx?pid=5881#ov

It says it supports 12/19~24v, however, I don't know if that means through the power input it already has. Not only that, I don't know how much wattage it can run at continuously.

On internal I/O reistors, it lists:

1 x 4-pin ATX 12V power connector

If that doesn't support 12V input I'd be pretty surprised. Also, it helps reading the manual:

DC Power Jack
Connect the DC power to this port. This port supports 12V/19V/24V power adapter of up to 150w. Note: The DC power jack cannot be used with the 4-pin ATX 12V power connector simultaneously as a source of power input.

[...]

ATX_12V (2x2 12V Power Connector)
This connector can be used to input power when the DC power jack on the rear panel is not connected. However, if the DC power jack is connected, this connector can only be used to output power

I would argue that this is a strong indication that the board can output up to 150W total of regulated DC, and it seems like the ATX_12V connector is part of that. So maybe you wouldn't even need an additional PSU, maybe you could power the GPU (as long as it's purely slot-powered) just with the on-board regulators?

It sounds like the ATX_12V pin also only accepts 12V, so it probably bypasses the 12V regulation altogether.