Hello,
currently i'm building a new 19" homelab, and i want to ask here before, could i use an ASROCK 4125-ITX (Intel Quad-Core 2,4 GHz with 1 x RJ45 Gigabit LAN on Board) / (8 GB RAM / additional ISA 90° Adapter (for build in a 1U server case) for use the Delock PCI Express 1.0 to 4 x RJ45 Gigabit LAN BCM? Then OpenWRT x86 64-Bit Image i want to flash on a internal Sata 256 GB 2.5" SSD Drive.
The Onbaord Lan i planed as WAN and the additional 4xRJ45 Gigabit over the ISA Card as LAN for different Subnets.
Does anyone have any experience with this non standard OpenWRT Hardware? Will the Kernel detect the Delock ISA Card?
Sorry for my bad english, but i think, everyone understand, what i mean .. 
Thx
x86 is a very standard router platform, and without knowing the specific network card, yes, it should work.
Unless you already own the 4125, or get it very cheap, there should be other, cheaper, solutions out there.
Hello,
actually i've the AVM Fritzbox 4040 with OpenWRT and it works great, but the Idea for the X86 comes, while i've many J4125-itx boards here at home.
This is the detail page from the manufacturer of the raiser LAN Card:
https://www.delock.de/produkt/88207/merkmale.html?setLanguage=en
The problem is, i'm not sure, if the OpenWRT kernel support this device lan card or not.
The motherboard has a PCIe 2.0 x1 connection. If your NIC really is PCIe 1.0, this means you'll get 250 MB/s of bandwidth (PCIe 1.0 x1). So it'll work, but you won't be able to fully feed 4 Gigabit connections.
OP's card should be PCI-E v2.0 standard (so with x1 all ports can run at full speed) and it's supported by upstream linux so there should be no issue to work with OpenWrt, however the driver by default is not installed, so when you download the image remember to include kmod-tg3 as a custom build.
I think the Broadcom card is still doing better than the Realtek so OP you might consider to use ports on the Broadcom card only (or leave the Realtek one for guest network)