Mellanox ConnectX-3 on ebay look strange

krista

New Member
Dec 22, 2015
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it appears these cages were to control airflow in a 1u ot 2u rack server. noisy little beasts of 40mm fans, sometimes 40x56mm!! and often shredding air at nearly 30,000 rpm while screaming like a constipated deamon child trying to pass yoko ono... while on fire. oh, and there's a large number of them. they're all blowing the same direction, usually front to back.

as they spin so fast and are very thicc (heh) they create a *lot* of static pressure, which is necessary to move air in a very compact and filled chassis. the longer and thinner air channels get, the harder it is to push air through, and the more static pressure you need to get the job done.

one *very* clever thing thermal engineers do while designing 1u systems is to balance and use the flow generated by these wee dangerous beasties† to cool everything without additional fans. you will notice heatsinks designed specifically ppl l
 

BeTeP

Well-Known Member
Mar 23, 2019
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Usually posters confirm the "greatness" of the deal (by communicating with the seller or just ordering a sample) before posting here.

As for your question, in this case the seller is "confusing" because they are either stupid (used wrong stock picture by accident) or plain dishonest. The price is not that great either. So hard pass.
 

gzorn

Member
Jan 10, 2017
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I don't trust ads that have obvious BS in them. ConnectX-3 cards run at PCIe 3.0, not 4.0. Also, I think that the 341 is a mezzanine card. I second the hard pass.
 

BeTeP

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Mar 23, 2019
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I got one. It is a mezzanine card mounted on an adapter.
This depending on the brand (i.e. mezzanine card standard) could be interesting just for the slot adapter alone. Nice thing to have for testing and whatever purposes. Can you post pictures?
 
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matthew5025

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Mar 21, 2016
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Attached more photos for the curious :D

I want to buy just the OCP to PCI-E adapter. Haven't been able to find one anywhere.
There's a pic of the adaptor too, hope it helps in your search!
 

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hmartin

Active Member
Sep 20, 2017
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The seller replied to my question and seems willing to discuss selling the OCP to PCIe adapter separately.

Quantity and price are still unknown. I'm assuming people would want an OCP mezz to PCIe x8 version?
 

int0x2e

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Dec 9, 2015
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The seller replied to my question and seems willing to discuss selling the OCP to PCIe adapter separately.

Quantity and price are still unknown. I'm assuming people would want an OCP mezz to PCIe x8 version?
Just out of curiosity, which OCP mezz cards are you guys trying to adapt to regular PCIe? I've got a couple of OCP based machines and most of my mezz slots are empty. It always seemed to me that regular PCIe cards were more cost effective, but I'm guessing there's something big I've been missing...
 

semidetached

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Sep 18, 2018
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Just out of curiosity, which OCP mezz cards are you guys trying to adapt to regular PCIe? I've got a couple of OCP based machines and most of my mezz slots are empty. It always seemed to me that regular PCIe cards were more cost effective, but I'm guessing there's something big I've been missing...
I grabbed one of these for a server that has an OCP slot to free up a PCIe slot, but it could be useful for anyone wanting a 40GbE ConnectX-3 Pro (for VXLAN or RoCEv2)
Mellanox MCX345A-BCPN ConnectX-3 40GbE QSFP+ PCIe 3.0 x8 Network Adapter Card | eBay
 

BeTeP

Well-Known Member
Mar 23, 2019
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The seller replied to my question and seems willing to discuss selling the OCP to PCIe adapter separately.
Often when I express genuine interest in some obscure and therefore relatively low priced item and start asking questions - my questions help the seller to discover item's true value and they raise the prices. So if the price is reasonable - I tend to buy first and ask questions later.
 
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int0x2e

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JustinClift

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Oct 5, 2014
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@matthew5025 Would you be ok to post some further pics of the mezzanine card itself?

In the photo's above there don't seem to be any markings of Mellanox nor board identifiers (part/model #, etc). I've never used a Mellanox mezzanine board before, so no idea if that's normal for them. With their PCI-E ones though, they normally have clear markings.

Really curious about the OCP to PCI-E adapter too. In the UK and Australia, the mezzanine cards are almost always cheaper on ebay (sometimes by a lot) compared to the PCI-E ones. Having a supply of those adapters - especially x8 or x16 - could open up some possibilities. :)
 

hmartin

Active Member
Sep 20, 2017
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Really curious about the OCP to PCI-E adapter too. In the UK and Australia, the mezzanine cards are almost always cheaper on ebay (sometimes by a lot) compared to the PCI-E ones. Having a supply of those adapters - especially x8 or x16 - could open up some possibilities. :)
OCP mezz cards are PCIe x8, there is no x16 mezz card to my knowledge.

The seller replied that for QTY 50, they wouldn't sell the OCP to PCIe adapter for less than the current price of the single port card ($22 USD + S&H) and they're not interested in listing the adapter separately.

So buying the adapter from them is not an economical option.
 
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JustinClift

Member
Oct 5, 2014
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Interesting. But they'd be willing to sell the adapter (x4, or x8?) with a minimum qty of 50? If so, what price (in total) for the 50?

If the adapters seem legit + price is reasonable, we might be able to split costs or something. :)
 
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