Intel Celeron J4105 based board with 3 PCIe slots

Hey Everyone! Newcomer here and excited to get started with OpenWRT.

I'm looking for an x86_64 based 4G LTE router. After doing a lot of research and also reading about the comparative throughput testing, I thought that it would be best to stick to Intel Celeron J4105 CPU moving forward since I really would like to achieve some good performance with OpenVPN based network. Since 5G cellular Internet is also, hopefully, going to be available soon, it would be nice to just have to switch the 4G/3G PCIe card with a 5G card for an upgrade and be able to get some serious speed upgrades that the Intel Celeron J4105 CPU can handle.

I really liked the boards by PC Engine, especially the apu4c2 which I would really consider for now. It's just that I wished that it had the Intel Celeron J4105 instead of the AMD GX-412TC. So basically this is what I'm looking for in the board (or even a setup, mini ITX maybe):

  • Intel Celeron J4105 CPU
  • 4 Ethernet Gigabit ports
  • 3 PCIe slots:
    • 1 for 2.4GHz WiFi
    • 1 for 5GHz WiFi
    • 1 for 3G/4G LTE (5G in the future) cellular internet
  • SIM slot for the cellular Internet
  • Optional: USB 3.0 Port(s)
  • At least 2GB RAM
  • SDCard for memory, no need for SATA or m.2

I've tried looking around in AliExpress but hardly found anything close to what I'm looking for, most of them have audio and video ports and just a single PCIe for the WiFi.

So to wrap things up I have two questions:

  1. Is there a board that matches or is close to what I'm looking for?
  2. I'm wondering if it is really possible to just upgrade to 5G Cellular Internet by just switching the 4G/3G PCIe card with a 5G supported one, does anyone know?


1 Like

Just an idea, add a second dedicated AP to operate the two WiFi radios, that way you only need to deal with the 4G/5G radio on the board (and only need one PCIe slot)?


As well as a USB-mPCIe/M.2 (depending on card) enclosure for the LTE modem.

The further you get from commodity configuration, the more expensive things get. Multiple mPCIe is far from the norm, as is a SIM socket or the M.2 socket for an LTE modem.

(I don’t have any 5G card info, but I’m guessing it will be M.2, not mPCIE. LTE modems are already going this way.)

1 Like

Yeah I thought about that and also about having a Gigabit Ethernet switch to get extra Ethernet ports. Though I'm thinking of having some monitoring with ease of setup and it would be somewhat easier to have everything within the same board/machine, that way I don't have to worry about accessing each and every component separately.

Plus I'm hoping to reduce the number of things having power adapters, generally just to save some cost too from buying the switch and APs and paying more electricity bills, although I'm not yet sure how much it would cost me to have everything in a single board so I'm considering all of them as options but want to see if I can get away with just the board. At PC Engine I'm seeing the board costing about 100$ and I'm ok with that for start since I know that I won't be needing an SSD/HDD for the router which adds a big factor to the cost.

My Cisco SG300-series switches consume under 10 W during normal, home-use conditions, as I recall. The advantages of even a L2 managed switch are huge, including performance, monitoring, and flexibility.

A USB stick can be had for under US$10. Quality SSDs start around US$30-40 if you want something faster, larger, or more robust.

A good-quality, complete, consumer all-in-one router can often be purchased for less than two mPCIe cards, 4/6 pigtails, and 4/6 antennas.

1 Like

I thought the USB-mPCIe (not mPCIe alone) is something to stay away from because of the extra layers it adds which slows down things right?

I didn't know that M.2 can be used for stuff other than storage, thanks for the info! I'm actually considering it now for 4G as well. That kinda means that I could get one of the fan-less boards with Intel Celeron J4105 from AliExpress, an M.2, a single mPCIe and 1 or more Gigabit Ethernet ports. It's possible to use the M.2 on the board for a network interface instead of storage right? I'm only asking because I've never seen them in action before...

I'm sort of a tinkerer and I would consider buying the mPCIe cards, pigtails, antennas and all just so to have an ease of mind not having to get a brand router because I've been using one for a while and I feel like I should ditch them for once and for all, primarily because I see so many 4G routers in the market around me and they're being sold expensively for poor performance and quality and always shortcoming in a feature of some sort.

I'm all ears (or eyes) for any suggestions you can think of. Thanks!

mitxpc might have something of interest.


Wow thanks!

Ok I checked out the M.2 and learned that there different M.2 slot or ports (A, B, E and M keyed). It seems that cellular and wifi cards use the E keyed, still checking though...

1 Like

First thing is that the J4105 is not "magical" among the various comparable CPU/SoCs available. Any of the low-TDP SoCs with comparable clock speeds, cores, and AES-NI should have similar performance.

I'm a tinkerer too, going back to the time of 6146 tube transmitters. As much as I enjoy making my own gear, when there is something commercially available that meets the requirements at a lower price, even before my time is included, that's hard to pass up. Quality, 100 mm pigtails are $5.90 each (Mouser, US). Antennas are a crap shoot, as I don't have test equipment that can measure at 2.4 or 5.5 GHz. "eBay" antennas are in the US$4-10 range. Call it US$10 per RF chain at best. So, for a dual-band, 2x2 setup you're at $40 just for antennas. If 3x3, then $60. Roughly what, US$30 per 802.11 card? You're at something like $100-120, without case. With decent-quality all-in-one units with current chip sets (ipq40xx, for example) available around US$75-100, it's hard for me to justify homebrew for onsies-twosies.

On USB, most of the mPCIe/M.2 LTE modem cards are USB-attached, not PCIe-attached.

Both M.2 and mPCIe have different signal population and even physical keying. If you look at the Sierra Wireless EM-series, you can see the M.2 versions, which is where they seem to be concentrating their high-performance devices (EM7565, for example).

1 Like ticks almost all boxes but is more than double price of APU.

1 Like

Cool! Thanks for sharing this company, mitxpc!

Hi! Just share my own config. It is beefier than j4105, this is not just a router but hypervisor with Openwrt, file server and other interesting stuff. I'v built it on G4900T low TDP CPU but with intend to change it to something more powerful later if there would any need for this. The main concept is a travel and SOHO backpack server for poor man (rich man can choose supermicro motherboard, SSD storage) Weigth is 1.7Kg with power adaptor, alumi case. Though case is not finished yet.

Current spendings ~470USD. 1 HDD not included, PS and pigtails I bought used, CPU was unpacked, but new, everything else - new, case DIY.

1 Like

TL/DR; switching to a mini ITX (SFFPC) with PCIe bifurcation for a standalone machine and support for multiple network cards for router feature.

So after quite some researching, I found myself becoming more ambitious in building a DIY server with a router feature. Although it might be an overkill for a router but I'm not planning just a router anymore, the build will also be a standalone machine to run many other things with being a router. I looked up and found that OpenWRT can be served as a docker image/container, this makes things really interesting.

With that in mind, I'm planning a build with mini ITX form factor (or SFFPC). I really liked the motherboards sold on MITXPC (thanks @anomeome) but haven't decided on one. There isn't one board with all the slots I need but I came to learn about PCIe bifurcation. Its a really neat thing to maximize the use of a PCIe slot, what it does is it lets splitting of a PCIe slot into smaller slots using a certain type of adapter (not PLX). The latest (coolest) use I've seen is connecting M.2 M-key SSDs, M.2 M-key uses PCIe x4 internally so one can connect 4 M.2 SSDs to a single PCIe x16 slot. I'm planning on doing the same but with network cards. This makes things really easy to support all sorts of network cards with different slots, be it a M.2 slot (needs a max of PCIe x4 for M-key) or a mini PCIe (needs a PCIe x1 slot only) or even regular PCIe x8/x4/x1, they can all be connected to the same PCIe x16 slot as long as the motherboard supports PCIe bifurcation.

So far I found a handful of chipsets in ITX form factor that support PCIe bifurcation, mainly the Intel Q370, Intel Z370, Intel Z390, and AMD X570 (has the newer/faster PCIe 4.0 instead of the 3.0 in the Intel ones). The thing the bifurcation splitting can be different from one motherboard to another. An x16 slot into can be split into x8-x8 or x8-x4-x4 or x4-x4-x4-x4 but not all motherboards support all of these configurations. This kinda makes me wonder which would really be adequate for my network cards and future upgrades.

So I want to decide on the network cards first before choosing the motherboard. I found my knowledge of network cards to be weak in this area although I can figure out the slots and their bandwidth needs.

Finally, the questions:

  • I see this often but haven't given it so much thought, do I need two network cards for WiFi if I to want create 2.4GHz and 5GHz WiFi networks with 802.11 a/b/g/n/ac? Reasons and any suggestions?
  • I'm hyped about getting a 4G LTE Cat8 card, is there one from a known seller? If not how about a 4G LTE Cat6 card?
  • Any 1Gb or 10 Gb Ethernet cards?

I'll keep looking but would appreciate your suggestions, thanks!

Well, you need two RF chains (for lack of a better word) tuned to the right frequencies that can be used simultaneously, theoretically these two could be located on one card, but I have no idea what the market offers. IMHO it makes more sense, to move the radios from the main router to dedicated APs as that will allow better placement for both components.

This sort of "server-consolidation" approach has a number of things going for it, like, since the router probably needs to run 24/7, it makes sense to add other server services on the same machine to avoid having more 24/7 machines, saving energy in the process.
The downside is that this will sort of link the safety and security of the different services (including firewalling and routing) together, so if one of the components fails it is more likely for the others to fall also (sure that is a continuum, with a real hypervisor probably being safer than containers, with containers in turn being safer than just running everything under the same OS).

1 Like

I can see the appeal of getting everything in one beefy box, especially if you need to route a high-speed line and at the same time want a capable (file) server. However, beyond the satisfaction of "being able to do it", I really don't see the benefit of integrating the wifi access point. Not only does it make everything comparatively expensive and complicated to set up -- it also ties down the placement of the access point to where you want to put your RouterServerBeefyBox (which you probably want to stow away somewhere out of sight and out of reach.)

Given your scenario, I would probably not integrate the wifi and instead get a relatively cheap (OpenWrt-supported) dual-band access point which I could then place somewhere central to distribute wifi. Maybe even one of those repeater-extender types with a single ethernet interface.


Unless you’re running a hypervisor or a secure container system (without any apps that require, for example, SysV shared memory), running more than router/firewall functions on your border is very poor security practice. Even then, it is marginal, at best.

1 Like

Yes that's what I have in mind, that's why I mentioned Docker as I am very fond of it.

docker is not a secure isolation.

1 Like