PCIe 2.0/3.0 4x Lane 10Gb SFP+ card?

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eroji

Active Member
Dec 1, 2015
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Are there any single (or dual) port SFP+ cards out there that runs on 4x lane? I am looking at specs for X520 and even the single port version says 8x 2.0 lanes, which seems way more it needs.
 

aero

Active Member
Apr 27, 2016
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pcie 2.0 is 500MB/s per lane bidirectional. 1-port 10gbe card max throughput is 1.25GB/s. 4 lanes of pcie 2.0 gives 2000MB/s, so enough for a single port, but not enough for dual ports. I'd venture to guess that manufacturers want to use as much of the same fab process as possible in creating their 1 and 2 port cards, hence the 8x required to fully utilize a dual port card.

edit: looks like you're in luck though...see this
[SOLVED] 10Gb Network Cards and PCIe 2.0 - Networking - Spiceworks
 

Aluminum

Active Member
Sep 7, 2012
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x8 cards work in an x4 slot, you may have to modify either the slot or the card.

In my experience the slot is a better option, while harder to get to you are a lot less likely to destroy hardware as you are only removing a bit of plastic at the end and not cutting any pcb or traces. Steady hands and a sharp exacto knife is all you need: even, steady and light pressure so if it slips you don't slice into the board.

If you are lucky your board already has open-ended x4 slots.

x4 2.0 is plenty of bandwidth for 1x10Gbe.
 
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markarr

Active Member
Oct 31, 2013
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I have found a metal hack saw blade works well. Tiny narrow teeth so doesn't slip and just the right width for a card.
 

eroji

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Dec 1, 2015
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My motherboard has plenty of x8 slots, but the remaining ones are only 4x eletrical, hence my question. I want to get a X520-DA1 for instance and put that to use.
 

AveryFreeman

consummate homelabber
Mar 17, 2017
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Near Seattle
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x8 cards work in an x4 slot, you may have to modify either the slot or the card.

In my experience the slot is a better option, while harder to get to you are a lot less likely to destroy hardware as you are only removing a bit of plastic at the end and not cutting any pcb or traces. Steady hands and a sharp exacto knife is all you need: even, steady and light pressure so if it slips you don't slice into the board.

If you are lucky your board already has open-ended x4 slots.

x4 2.0 is plenty of bandwidth for 1x10Gbe.
That sounds like a job for my Dremel wheel!! *whiiizzzzzzzzzzz*
 

fohdeesha

Kaini Industries
Nov 20, 2016
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My motherboard has plenty of x8 slots, but the remaining ones are only 4x eletrical, hence my question. I want to get a X520-DA1 for instance and put that to use.
if it physically fits it'll work no problem. I have a few 10gbe single port cards in x4 electrical (x8 physical) slots and they saturate my data tubes at maximum rates
 

diskdiddler

Member
Mar 3, 2017
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I'm looking at purchasing one of the SuperMicro Atom boards (PCI-e 3.0 4x slot)
and one of the Mellanox PCI-e 2.0 cards - but they're using 8x.

I'm fine with hacking out some of the fibreglass slot, no problem, I'm more concerned about the limitations. Is PCIe 2.0 at 4x really enough for 1.25GBytes /s ?
 

diskdiddler

Member
Mar 3, 2017
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So to clarify, I can buy *any* PCI-e 8x card, grind out a slot for the plastic and it'll just run at 4x not 8x mode?

(I just saw a picture of my planned Atom board from SuperMicro and upon closer inspection I THINK they've actually left the slot open at the back anyhow?)

This is reassuring, thanks for this thread guys.
 

diskdiddler

Member
Mar 3, 2017
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I know, I thought it could do with another boost, it's a pretty important thing, I think a lot of people might not be aware of.
 

Docop

Member
Jul 19, 2016
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Well it's not fully clear. Actually : a 1 port 10gb nic card running pcie2.0 x4 , if i plug into a pcie3.0 x1 : Will this work at about 5gb speed ? But work without error, just a bit slower.. ?
thanks