MXM Power Connector

Hello All!

First time poster, overnight viewer. I've spammed this forum the last 12 hours trying to find the name for MXM external power connectors.

I am working on a custom project that takes a STX MXM motherboard and uses it for my main gaming pc (I only play World of Warcraft XD). But to get the GPU I want, Clevo RTX 2070, requires external power.

My next move is creating some sort of adapter to power these GPUs. But I have no idea about pin layout, a closer look also shown here in a recent post.

Any help is appreciated and I believe @Khenglish is rather versed in these, if you are able to help. Thanks!

These are the main motherboarrds I have been looking at:
B360 STX MXM
https://detail.1688.com/offer/597442006068.html?spm=a26352.13672862.offerlist.95.55e272ffWFsUDE

Z370 STX MXM
https://primebuy.com/product/asrock-mxm-ipc-q370-12v-motherboard-2xm-2-key-m-1xm-2-key-e?msrc=gglds

 

Not only do you need external power, you'll need to modify your MXM slot for the 1.8vE and 3.3vS wires - You can basically follow this thread:

http://forum.notebookreview.com/thr...ix-gets-an-8700k-and-gtx-1080-upgrade.814711/

The power connector for Clevo MXM itself can be sourced from HP laptop power jacks - Many carry the right connector, with between 4 and 8 pins. You want the 8-pin variety, and they can be had for less than $10.

I've performed this mod on my own Asrock Deskmini B250 board, but I was working with a deficit of cards at the time, and undid the mod. I will be reattempting this soon.

 

Do you know the pinout on this connector? Would you just connect another DC power connect to it or wire it internally?

Then I summon @Mr. Fox as well for his small large, very large insight.

 

Yeah, it's exactly like this:

https://i.imgur.com/VsU60sn.jpg

Should accept standard 19v, I'd suggest sourcing that from the power side of the adapter on the motherboard, not direct from the plug.

 

Feel free to browse my imgur album and use anything you find useful. I am by no means an expert or genius at this stuff. I merely grab information from people that know more than me, such as @Khenglish, @Prema and lots of other people that know more than me. It probably would not be far off base to call me a hack. I know just enough to be dangerous and I am sometimes daring (or dumb) enough to take a stab at something crazy.

P870DM-G 8700K and GTX 1080 Mod

 

That's wonderful. I guess my only true question is to verify the external connector takes 19V or is it 12V like a PCIe connector. I'm an electrical engineer so I can most likely do some of the mods with some direction. Assuming Khenglish explains the process. My only thought is with a STX motherboard, there isn't auxiliary power I can use to power the MXM external power. Id have to adapt a PCIe connector or a DC Adapter depending on voltages. I really hope it isnt something like 3.3V. I could look up pinout for the auxiliary ports on your laptop mod.

 

The left 4 pins are 19V power and the right 4 are GND. The GND through the MXM slot is substantially stronger than this cable and you don't need to connect it. You do need to add the 19V lines though. 10 series use it for the RAM and 4/6 of the core phases. 20 series exclusively use the power cable with zero use of the 19V power tab on the MXM tab.

 

So my only question here is how would you go about creating this adapter at 19V? Would you just get a normal DC Dell power jack and split the normal adapter input to the board and to the card?

 

This specifically for the GPU and then a splitter like this

 

That would be bad. You need to not bypass the power switch on the motherboard to power the card. Either solder a wire to the 19V pins on the MXM connector, or to the output of the power transistors on the motherboard.

If you give me a picture of the motherboard I can show you where to grab power from.

 

I will have to get back to you on that lol. Still trying to find a few. If you happen to stumble upon any DeskMini GTX's let me know lol Those seem like a good bet but are very rare.

There is also this though, but its very expensive.
https://primebuy.com/product/asrock-mxm-ipc-q370-12v-motherboard-2xm-2-key-m-1xm-2-key-e?msrc=gglds

 

@Khenglish I have seemed to find a good motherboard at a decent price.

https://ebay.to/2Z0JF35

This also seems to come with a few wires shown in photo 7 of 7. Can you make out what all is there? It looks like SATA cables and a ribbon cable for something.

Also the motherboard claims Type A or Type B MXM compatibility, up to 150W. I am unaware of this format, just MXM3.1, etc.

 

2x data and 2x serial type I/o back panel adaptors.

 

MXM power switch transistor is boxed in red. Solder a wire bridging all 4 pins in the green box for the power cable. I am assuming that since this is a desktop that MXM power is 12V, and not the normal 19V like on laptops.

Also only 1 transistor is concerning. That thing may explode with cards over 100W.

 

Perfect, and this would still require the earlier mod to the MXM connection as well to support 10 series and 20 series MXM?

 

Also assuming that pin 4 is GND?

 

GATE

Don't ground that...

Yes you need the 3 3.3V wires and the 1.8V enable wire.

 

I could probably find it when I get the board, but you have an idea of where to ground the MXM external connection.

 

You can ground it to anything that's ground. You also don't need to connect it at all.

 

The person selling me the MXM GPU said Clevo cards also have a software protection as well as the 2 physical protection (fixed by the 3.3V connection and the 1.8V Enable mod assumably). Do you know of such software protection? Sorry for asking so many questions.

 

@DefinitelyCam I don't believe that seller is correct, unless he just means the possible driver problems, which are across all MXM cards across all brands.

It's entirely a crapshoot as to if the drivers will work out of the gate, or with modifications, or at all. I'm reasonably confident it will just work for this case, it's usually the weirder cards which act up.

 

The 10 and 20 series work in the ancient EM series with mods so I can't image there being any software protection issue.

 

It's not really an issue with the latest cards anyway as they are different shapes and the standards are the same if the shape is the same usually.

MXM compatibility is really machine by machine and card by card though.

 

At this point its really important to view the sustainability aspect. You can get for the same money a proper used GTX1070 or GTX1080 with close to equal performance and Mainboard, RAM etc. to boot.. Then when the availability of the 3000 cards lowers down to affordable sums you can upgrade down the road.

Going for an MXM graphics-card is the least cost effective option tbh. Its just that "enthusiasts" who go for a Clevo System that has all the upgradability, dont care much about the cost to benefit aspect and rather have a laptop that can outrun a desktop pc. Forking over mulitple loads more for that effect is sadly reality.

I honestly bought my KM1-system on the cheap as a barebone and filled it to the brim with my old parts from my old rigg. My excuse was the possibility of a laptop that can be used like a server 24/7. On that note it has been lately faltering but i guess maintenance is a repetitive process in that concern.

 

The cost benefit of an MXM card really depends on the system and the price you get for the old card and the new card.