PCIe x16 Risers/Port Bifurcation on Home Grade Equipment

Allan74

Member
May 15, 2019
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0
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First, I hope this thread is in the right spot as it hits a couple or more 'check boxes' in terms of subject matter.

To begin....
Has anyone had any experience with single source/bifurcation risers such as the Supermicro RSC-R2UG-2E4E8 ?
(x16 to tripple x16 physical)

Of those that are familiar with such hardware, has anyone had any luck on something such as a Mini-ITX Motherboard, say, for a Home Router Project ? ...and running either Linux or BSD ?

At this point, before I say something stupid, I will upload an image file to reflect on, as my 'Big Boy' words don't have the technical range to cover many of the questions that I would like to ask, so hopefully the simple pic can help clear up some of what I am proposing to accomplish.

Idle Hardware, as with Idle hands, are the Devil's Playground. Rather than get rid of things that I am not using, I figure I would put that which I already own to use....and perhaps add a couple more pieces in the process.

Hardware:
- Asus P8H61-I (ITX, Intel H61 Chipset) Motherboard (supports up to Core i7 3770 4c/8t if needed)
- Core i3 2100 (2C/4T, 3.10Ghz)
- 8GB DDR3 Memory (can add more if required)
- Supermicro RSC-R2UG-2E4E8 Bifurcation Riser *** (everything hinges on this item)
- PCIe x1 Wifi
- PCIe x4 4port Gigabit Ethernet
- PCIe x8 Twin SFP+/10GbE

My goals with this project are to simply add some 10GbE to my home network (at the source) to save from buying a 10GbE switch, and eliminating the direct connection between my media server and main workstation, and simply play with a Firewall/Routing Distro. Everything is within close physical proximity already, I simply want to go back to a single NIC in my workstation and Media Server....and not have to buy a switch.

I guess you could say that I have a BEST and WORST case scenario laid out in my mind already, but am hoping for the best. Please see my attached image to clear anything up that I may have missed, or to put things into greater context.

Thanks in advance,
Allan
 

Attachments

Aluminum

Active Member
Sep 7, 2012
431
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Bifurcation requires hardware and bios support, an H61 board from years ago definitely has neither.

Mostly only newer server/HEDT motherboards (X-series chipsets) support this. There are a few ITX and consumer boards that can 2x8 to x16, asrock did it first along with some very recent asus models. Typically only in their high-end 'gamer' Z-series boards.

I have 4x4 to x16 nvme adapters for my TR boards, they work great.
 

BeTeP

Well-Known Member
Mar 23, 2019
517
323
63
Passive PCIe splitters require bifurcation support by motherboard. Active splitters (with PLX bridge) might work but they usually cost more than your whole system. You can get another older Haswell based system with more PCIe slots for half the price.

For example you can get the whole HP ELITEDESK 800 G1 SFF (i5-4570 + 8Gb RAM) for like $100.
It will give you on-board Intel I217LM (much better than RTL8111E your Asus mobo has) and 4 half height PCIe slots:
  • (2) PCI Express x1 (v2.0)
  • (1) PCI Express x 16 (v2.0 - wired as x4)
  • (1) PCI Express x16 (v3.0)
You would install the dual 10GbE card into the PCIe 3.0 x16 slot (closest to the CPU), your quad GbE into the PCIe 2.0 x16 slot and the WiFI card into any of x1 slots. You better have HH brackets for all of them.
 
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ReturnedSword

Active Member
Jun 15, 2018
204
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Santa Monica, CA
Intel has never to my knowledge enabled bifurcation on their consumer (or consumer-derived) platforms until the Z170. Even then it's just a simple x8/x8, or x8/x4/x4 on later platforms. The important thing to note is that it must be enabled by the BIOS also. You'd need a Z- or X-series chipset though as well.

I'm not the foremost expert on router appliances, but I have run my own routers for many years now. Currently I'm using pfSense, after migrating from m0n0wall years back.

My advice is not to have your router appliance also be the WiFi AP. This complicates things a lot, considering you can get a separate router for cheap and disable the DHCP server making it a much better AP than a WiFi card in your router appliance will ever be. I'm using a trio of ASUS TM-AC1900's I bought from T-Mobile for cheap ($60 each for two a couple years back, and $40 two years ago). T-Mobile seems to have a stock of them and they offload them for a decent price every so often. You can flash them to stock ASUS RT-AC68U firmware (they're just rebadges with a couple security checks in the firmware). If you feel fancy you can get the Ubiquiti APs which are competitively priced, especially on sale.

On using your router appliance as a soft-switch, I haven't attempted that, however I've read that the performance isn't that great. I'd also imagine your Sandy Bridge i3 would struggle.

I'd stick with keeping it simple, using the quad-port NIC in your PCIe slot, and wiring out your available ports to an AP. For 10 Gbps, you can direct connect devices for faster transfers.
 

anomaly

Active Member
Jan 8, 2018
189
38
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Unless I have a dud, my AOC-SLG3-2M2 card installed on a X10SDV-7TP4F is not recognized properly (only one slot x4 working). I can confirm my ASRock Threadripper MB works just fine with anything involving bifurcation. BIOS needs to be updated.