Dual Prot Mellanox Connect x3 SFP+ for 60$

skelleton

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Nov 4, 2015
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I could only find a 10GBE model for the MCX312A-XCBT, so I am reasonably sure they are 10G.

I ordered two. If they truly are only 1G, I can probably sell them without a loss here in Germany. Not sure when I will be able to test them though
I still did not order the CPUs for my new Server yet and Shipping from the US can take a while.
 

sfbayzfs

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May 6, 2015
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Yes, AFAIK, since they are all 10G SFP+ cards, and direct connect SFP+ Twinax cables are all supposed to be universally compatible (unlike optics modules)

ConnectX-2 are PCIe 2.0, whereas ConnectX-3 are PCIe 3.0.
 

izx

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Jan 17, 2016
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In the description it says Manufacturer: HP. With older HP Mellanox cards (ConnextX Original with CX4 connectors), I know you had to "cook" the firmware and cross-flash the cards to Mellanox generic. Fortunately the Mellanox flasher is fairly intuitive and it's not hard to do so. Of course, these HP versions were a lot cheaper at the time than the Mellanox branded ones.

Fantastic price. Now where are the 40QDR/56FDR ConnectX-3's for cheap...
 

bmacklin

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Dec 10, 2013
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geez. And I had just bought a x540-t2 today. For some reason I thought SFP+ cables are like $100+. Two of these cards and cables will still be less than what I paid for the x540-t2. Besides cost, any reason to choose one over the other?
 

izx

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Jan 17, 2016
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Besides cost, any reason to choose one over the other?
Depends on why you chose 10Gbase-T to begin with. SFP+ cables are more expensive compared to Cat6, of course, but 3-5m direct attach for $20 or so is par for the course on eBay. Of course, passive SFP cables won't go anywhere near the 100m limit for Cat6; you'll need optical for that.
 

izx

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Jan 17, 2016
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What I really want is one (well, 2-3) of the dual-port ConnectX-3 VPI cards so I can do ad-hoc 40/56IB and still have another port free for auto-negotiated 10GigE...seem to go for about $200 though....
 

bmacklin

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Dec 10, 2013
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Depends on why you chose 10Gbase-T to begin with. SFP+ cables are more expensive compared to Cat6, of course, but 3-5m direct attach for $20 or so is par for the course on eBay. Of course, passive SFP cables won't go anywhere near the 100m limit for Cat6; you'll need optical for that.
Not sure really. Mostly because it's familiar compared to Cat5, etc.

Half height is kind of killing it for me. I don't have a rack yet.
 

izx

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Jan 17, 2016
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Not sure really. Mostly because it's familiar compared to Cat5, etc.
The pure 10GigE/40GigE Mellanox cards are plug and play with SFP+/QSFP cables. Read model number carefully, google it and double check with the Mellanox "product brief" PDF that will show up in the results to confirm it doesn't involve Infiniband.

If you want low-profile, here's a 2-pack of older ConnectX-2 dual-port 10GigE cards for $120. Check the ConnectX2-EN brief to see what you'll be missing compared to the ConnextX-3 the OP card is using.
 

T_Minus

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Feb 15, 2015
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What I really want is one (well, 2-3) of the dual-port ConnectX-3 VPI cards so I can do ad-hoc 40/56IB and still have another port free for auto-negotiated 10GigE...seem to go for about $200 though....
They go for 130-150 you just have to keep an eye out ;)
 

sfbayzfs

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May 6, 2015
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From the pictures they look like low profile - a while ago someone said that you can get them from Mellanox support, I got 4 and will test this theory after they arrive (just in case they want serial numbers or something)
 

izx

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Jan 17, 2016
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I think they give out brackets for cards that are not EOLd (which these arent).
 

bmacklin

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Dec 10, 2013
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I think they give out brackets for cards that are not EOLd (which these arent).
I got two. Will be trying it out as well. Exciting! First time using NICs that aren't RJ-45s!

So how long can the passive twinax cables go?
 

izx

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Jan 17, 2016
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So how long can the passive twinax cables go?
The experts will chime in, but I think 10m tops? At least those are the longest passive cables I've seen. The internal conductor gauges decrease (become thicker) as the lengths increase, so longer cables can become pretty unwieldy if you're not using all the length.