Asus XG-C100-F network card

The Asus XG-C100-F is a current model of PCIe network card equipped with a single SFP+ cage capable of speeds up to 10 Gbps. In the EU, it sells in new condition for around 100-200 €, but is cheaper e.g. in the US. Recently, an eBay seller based in Lithuania advertised a batch of 30 of these cards in used/tested condition for only 40 € each, which made it a bargain difficult to resist.

I have no connection to the seller, except for my purchase of one card - search eBay for second-hand Asus XG-C100-F if interested. At the time of writing, the seller still has 21 of these cards available, so if you are in the EU, need one or a few of these cards, and aesthetics are not important for their use, you may take advantage of the present availability.

The heatsink of the card is relatively large and solidly attached to the PC board of the card with four screws. You need not worry about the heatsink being only glued to the LSI package like in some cheap chinese network cards, which involves the risk of the heatsink detaching with accidental impacts or vibration. The heatsink appears to be in contact with only a single LSI package on the card, not with the cage. As supplied by Asus, the card is accompanied by a low-profile replacement bracket. The SFP+ cage and a status/traffic LED are the only externally visible details.

Asus also markets the XG-C100C V2 network card, which is physically similar but equipped with a smaller heatsink and an RJ45 10 G port, and the PCE-C2500, an RJ45 2.5 G PCIe network card devoid of heatsink. I have no direct experience with these models.

My PC workstation is equipped with a relatively modern Asus ROG STRIX Z490-E GAMING motherboard, which makes a modern network card from the same maker a better bet against the risk of incompatibilities than a random combination of components from different makers. This motherboard has a built-in 2.5 G RJ45 Ethernet interface, which is fast enough for most uses, as well as a Wi-Fi 6 interface. However, I am in the process of upgrading the routers and switches of my home network to 10 G-capable equipment, and it makes sense to also equip my PC workstation with a network card capable of the same speed.

In my network, I decided not to use 10 G RJ45 interfaces because they use quite a bit of power and get very hot. Instead, I am using a combination of 10 G SFP+ optical transceivers and both multimode and singlemode optical fiber, which use far less energy and run cooler. I am still using the existing Ethernet copper cable in the walls of our apartment at 1 Gbps for connection to the edge router and ISP. This is not a throughput bottleneck, since my current ISP subscription speed is limited in any case to 250/250 Mbps.

The card (Figure 1) is in good overall condition except for some ugly scratches on the heatsink, which look like someone clumsily tried to remove the Asus brand (for what reasons, I cannot even begin to hazard a guess), and a little additional wear of the heatsink surface that suggests these cards have been carelessly tossed around together for a while, without any packaging.

Configuration

A quick googling led me to the page for this card model on the Asus web site. The very simple user guide only says to power off the PC and disconnect it from mains, then plug in the card in an empty PCIe slot, and finally to power up the PC and install the drivers.

Windows 10 does not recognize this card, so nothing happens without the Asus driver. The driver installation on Windows 10 Pro 64-bit was uneventful, required no change to the few default settings, and the card came online immediately, without requiring a reboot.

Once equipped with the proper transceiver (MikroTik S+85DLC03D in my case) and a suitable fiber connection to the closest optical switch, the 10 G link came on by itself and became the default network connection to the Internet.

I upgraded my workstation to Windows 11 days after installing the XG-C100-F, and the card continues to work without a hitch. All three network interfaces can be left simultaneously enabled, but only the XG-C100-F is displayed as connected to the Internet. The RJ45 interface is used as fallback if the optical link goes down.

Note that your PC may fail to connect to the Internet after a reboot, if two or more physical network interfaces are connected to the same network. In this case, you need to disable all the network interfaces causing the problem, less one, in Settings, Network & internet, Advanced network settings, Network adapters. It makes sense to leave only the fastest of these interfaces active.

Throughput and performance

At present, I am unable to measure the throughput of the 10 G link between XG-C100-F and router, because I have not found software for this purpose that runs on both Windows and RouterOS. I will be able to measure throughput only when I have a second PC with the same or a similar 10 G network card, and in this case I will need to directly connect the two PCs together, to avoid measuring the aggregated throughput of a PC-to-router-to-PC link.

There is an overabundance of software, both free and commercial, to measure the throughput of an Internet connection (which usually requires a number of dedicated servers on the Internet, specific to the test software being used), but measuring LAN throughput between different types of network devices does not seem to have been a priority for developers. I am only aware of software to measure Windows PC-to-PC throughput, and MikroTik routers have built-in utilities to measure router-to-router throughput (but not for benchmarking connections to third-party devices).

Summary

The Asus XG-C100-F PCIe network card is equipped with an SFP+ cage and provides speeds up to 10 G. Installation of both the card and the software on a Windows 10 PC with a recent Asus motherboard, and its subsequent upgrade to Windows 11, were easy and problem-free, and the link to a MikroTik router via MikroTik 10 G multimode transceivers and OM3 fiber is stable and error-free.