PCIE 3 x8 adapter for OCP 2.0 cards - $18

foureight84

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I bought two of these cards to test and they are pretty awesome. The ones I bought are referenced as 'OCP adaptor for all'. I was able to grab two ConnectX4 MCX4411A-ACAN off another seller on eBay for $25 each to test and they work as expected.

I think $18 is a pretty good price to be able to reuse decommissioned OCP cards that usually go for pretty cheap compared to their PCIe variants. I don't know if OCP type 2 will work with this adapter as the seller mentioned that they do not have access to type 2 cards to test.

Here are some iperf3 tests I ran from my computer to my NAS over the two ConnectX4 cards:
Screenshot 2022-05-25 165615.jpg
Screenshot 2022-05-25 165635.jpg
 
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applepi

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I tried this on a Chelsio T6 100gbps card and a CX3 card. The T6 popped some on board regulators and the CX3 card would not post. I would be careful with these adapters. I would not use them on OCP 2.0 cards.
 

foureight84

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I tried this on a Chelsio T6 100gbps card and a CX3 card. The T6 popped some on board regulators and the CX3 card would not post. I would be careful with these adapters. I would not use them on OCP 2.0 cards.
That's good to know for reference. Which adapter did you use? They sell one with and one without a buck-boost converter.
 
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int0x2e

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I wish I could find the reverse adapter - an adapter to connect a regular pcie card into an OCP mezz slot...
I've got a couple of the Dual Xeon-D boards that I would love to use with custom cards.
 
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Samir

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Since none of these are here in the US, I wouldn't mess with any of these unless you like being a guinea pig. At lease one person in this thread has had cards damaged by these adapters so know knows what else won't work right, etc.

If startech makes something like this I'd trust it, but otherwise I wouldn't.
 
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Cruzader

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Since none of these are here in the US, I wouldn't mess with any of these unless you like being a guinea pig. At lease one person in this thread has had cards damaged by these adapters so know knows what else won't work right, etc.
Considering that these have been used for years already its a bit late to be a guinea pig.
There is no advanced mystery tech here, its just pin to pin physical connector adapters.

To damage a card you need to use the wrong adapter for the card.
If you connect 400v to a 230v appliance and destroy it, do you blame the cable?
 

Samir

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Considering that these have been used for years already its a bit late to be a guinea pig.
There is no advanced mystery tech here, its just pin to pin physical connector adapters.

To damage a card you need to use the wrong adapter for the card.
If you connect 400v to a 230v appliance and destroy it, do you blame the cable?
If that was the case than a reputable company like startech would be making them and putting the wrong adapter/card won't blow something as there would be protections against it.

You can't blow out an sas1 drive by connecting it to a sas3 controller and vice versa because people that design these things are after more than just a quick buck. OCP cards aren't exactly disposably cheap, and if the standard is established then blowing cards shouldn't be an issue if the standard was designed correctly or adhered to.

Bottom line is that most 'direct from china' stuff like this comes with a bunch of caveats and/or half truths so buyer beware--especially when there isn't a legit counterpart made by a reputable company.
 

Cruzader

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If that was the case than a reputable company like startech would be making them and putting the wrong adapter/card won't blow something as there would be protections against it.
There is no "if that was the case" it is the case...

Startech etc wont make adapters like this because there is no demand for them in the market using these cards.
And homelab its faaaar to small a niche to be worth making.

Thats why these are open source designs that have been available as kits for years, because there is no commercial demand.
OCP/Mezz is regular pci-e but on a custom header, so you just need to do the correct pin to pin conversion.


OCP cards aren't exactly disposably cheap, and if the standard is established then blowing cards shouldn't be an issue if the standard was designed correctly or adhered to.
Its upto the user to adhere to using the correct type of card.
These are not consumer products, they are highend addon cards and they expect the users to use the correct type.

There are multiple standards/pinouts using the same physical connector.
Use the wrong standard/pinout card and you might fry it, regardless if using adapter or not.

Several brokers have made small runs of this type of adapter to resell OCP cards, mainly US ones.
Gotta love the irony of a European design mainly used by Americans is "direct from china stuff"?


This is same as the adapters to use HPe/Dell nics as regular pcie, open source designs that sometimes small sellers make batches of to sell.
But there is no commercial demand so no large brands will bother to make them.
 

Samir

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There is no "if that was the case" it is the case...

Startech etc wont make adapters like this because there is no demand for them in the market using these cards.
And homelab its faaaar to small a niche to be worth making.

Thats why these are open source designs that have been available as kits for years, because there is no commercial demand.
OCP/Mezz is regular pci-e but on a custom header, so you just need to do the correct pin to pin conversion.



Its upto the user to adhere to using the correct type of card.
These are not consumer products, they are highend addon cards and they expect the users to use the correct type.

There are multiple standards/pinouts using the same physical connector.
Use the wrong standard/pinout card and you might fry it, regardless if using adapter or not.

Several brokers have made small runs of this type of adapter to resell OCP cards, mainly US ones.
Gotta love the irony of a European design mainly used by Americans is "direct from china stuff"?


This is same as the adapters to use HPe/Dell nics as regular pcie, open source designs that sometimes small sellers make batches of to sell.
But there is no commercial demand so no large brands will bother to make them.
Even the most niche thing that I wouldn't imagine has any demand seems to be made by startech as that's basically all the company does. Otherwise, it's usually just too crappy to use, and someone in this thread blew a card due to the crappy designs so instead of touting this as 'buyer beware', don't sit here and 'blame a user for getting the wrong crappy adapter'.

If these ever really become a solution, someone reputable will make them--otherwise it's just more crap peddled from china, no matter who's design it is.
 

foureight84

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Even the most niche thing that I wouldn't imagine has any demand seems to be made by startech as that's basically all the company does. Otherwise, it's usually just too crappy to use, and someone in this thread blew a card due to the crappy designs so instead of touting this as 'buyer beware', don't sit here and 'blame a user for getting the wrong crappy adapter'.

If these ever really become a solution, someone reputable will make them--otherwise it's just more crap peddled from china, no matter who's design it is.
I don't disagree with you on that. A lot of these are experimental and do it at your own risk. I mentioned that I was able to test them on 2 ConnectX4 cards which I got for pretty cheap. It's one of those things that you shouldn't go out of your way to use on expensive hardware or even out of desperation. But if there's something destined for the landfill then being able to repurpose it is nice.

It was unfortunate for applepi that the variant he used killed his Chelshio card, and I assume he was doing so knowing the risk. Even if he used the other adapter variant, we wouldn't know if that would have worked either. But with the DIY spirit in mind (I don't recall if it was in this forum or another) someone had tested using a Supermicro pice splitter riser and ended up killing the connected card. I was about to test that same exact configuration until I saw the post and opted to buy a bifurcation card from C-Payne PCB Design instead and that worked out marvelously. (The C-Payne PCB Design is also a DIY project I believe).

We now also have this thread for anyone else wanting to give it a try. It's at least slightly more helpful than a blind gamble that comes from buying from an unknown seller in China.
 

Samir

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I don't disagree with you on that. A lot of these are experimental and do it at your own risk. I mentioned that I was able to test them on 2 ConnectX4 cards which I got for pretty cheap. It's one of those things that you shouldn't go out of your way to use on expensive hardware or even out of desperation. But if there's something destined for the landfill then being able to repurpose it is nice.

It was unfortunate for applepi that the variant he used killed his Chelshio card, and I assume he was doing so knowing the risk. Even if he used the other adapter variant, we wouldn't know if that would have worked either. But with the DIY spirit in mind (I don't recall if it was in this forum or another) someone had tested using a Supermicro pice splitter riser and ended up killing the connected card. I was about to test that same exact configuration until I saw the post and opted to buy a bifurcation card from C-Payne PCB Design instead and that worked out marvelously. (The C-Payne PCB Design is also a DIY project I believe).

We now also have this thread for anyone else wanting to give it a try. It's at least slightly more helpful than a blind gamble that comes from buying from an unknown seller in China.
Okay, I see your point, but then these are a great deal to experiment with. But they're not necessarily a solution to anything as there's a good chance of popping something.

Personally, I wish the 'gamble sellers' would stop as that market would return domestically in the us--heathkit, radio shack, and all the places I remember were killed by all these 'cheap' imports whose only purpose was to destroy domestic industries and jobs.
 

jmsq

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Okay, I see your point, but then these are a great deal to experiment with. But they're not necessarily a solution to anything as there's a good chance of popping something.

Personally, I wish the 'gamble sellers' would stop as that market would return domestically in the us--heathkit, radio shack, and all the places I remember were killed by all these 'cheap' imports whose only purpose was to destroy domestic industries and jobs.
As far as I can tell, they're effectively manufacturing an open-source design: GitHub - KCORES/OCP2PCIe: OCP Mezzanine card V2.0 to standard PCIe slot adapter design. Anyone can build/manufacture this, but at least at the moment no one domestically is choosing to. I'd rather have one option than zero in this case because I don't have the time or resources to build it myself. I strongly doubt that by them not making this, that the domestic market will magically step in on such a niche product.

There have been higher quality adapters in the past (see https://forums.servethehome.com/index.php?threads/mellanox-connectx-3-on-ebay-look-strange.26186/) unfortunately those adapters weren't available separately from the NICs, and now they're completely unavailable as those batches have long sold out.
 

Samir

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As far as I can tell, they're effectively manufacturing an open-source design: GitHub - KCORES/OCP2PCIe: OCP Mezzanine card V2.0 to standard PCIe slot adapter design. Anyone can build/manufacture this, but at least at the moment no one domestically is choosing to. I'd rather have one option than zero in this case because I don't have the time or resources to build it myself. I strongly doubt that by them not making this, that the domestic market will magically step in on such a niche product.

There have been higher quality adapters in the past (see https://forums.servethehome.com/index.php?threads/mellanox-connectx-3-on-ebay-look-strange.26186/) unfortunately those adapters weren't available separately from the NICs, and now they're completely unavailable as those batches have long sold out.
The problem is that because of these type of manufacturers, the domestic ones were driven out of business in the first place. Standard playbook--undercut, destroy, monopolize, profit! I would rather have the domestic manufacturers that work within the constructs of rule of law that don't have to compete with sweatshop unethical cheaters who don't play by rules and live for exploitation of their customer base.
 
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