When you're looking at motherboard features for your next PC build or upgrade, one of the most important specifications is how many PCIe lanes it supports, thanks to the combination of CPU and chipset. The better your motherboard, the more lanes you have for your graphics card, NVMe SSDs, and peripherals. But with modern consumer platforms from AMD and Intel, does stressing yourself out over how many PCIe lanes you have make sense? After all, both Ryzen 9000 and Arrow Lake have similar PCIe lane support. It's not quite as clear-cut as not having to worry, but there are still some pitfalls when you choose your motherboard that you'll need to be aware of.

Motherboard PCIe lanes are only half the story

PCIe lanes come from your CPU as well

The number of PCIe lanes your motherboard has can be stressful, but I have some advice that might help. If you find yourself stressed, take a step back and consider what you want to use your computer for. For most users, having lots of PCIe lanes for their graphics card and enough lanes for a speedy NVMe SSD is enough, and that's partly why motherboards and modern CPUs have the PCIe allocations they do.

Most computing tasks use one storage device and one graphics card at a time, and that's not going to change any time soon. Yes, you can use RAID to turn multiple storage drives into a faster array, but NVMe is so fast already that you'll need to use specialized workloads to max out that connection and, at that point, you might want to consider upgrading to a non-consumer platform. Motherboard RAID sucks and is easy to break, losing your data.

And while PCIe lanes are backward and forward compatible (running at the lowest speed of the combination), you can't just take 8 PCIe 5.0 lanes and make 16 lanes of PCIe 4.0, even if the bandwidth of those lanes is similar. HEDT platforms like Threadripper give you up to 128 PCIe lanes, and they're all usable on the right motherboards. But that's more than the usual consumer will need, which is why most motherboards only have a small selection to use.

PCIe lanes aren't just for GPUs and NVMe storage

Every motherboard will have a block diagram that shows where the PCIe lanes are apportioned. Apart from the CPU lanes, the chipset ones can be divvied up by the manufacturer in several ways, which all depend on the chipset constraints. It's not like you can look at the 24 PCIe chipset lanes on an Intel Z890 motherboard and say "I want 24 x1 lanes for storage," or some other configuration.

PCIe lanes are handled by root ports, and each root port can support a number of PCIe lanes (which can vary depending on CPU, platform, and chipset). For example, Intel's Z890 chipset can have up to 24 PCIe lanes, with up to 14 PCIe root ports. Enabling a Gigabit Ethernet port on the motherboard drops the available PCIe root ports to 13, and adding higher-speed wired networking will take up more PCIe capacity.

Other high-speed connectivity like Thunderbolt or USB4 will also take up PCIe lanes that could be used for storage or other devices, but those lanes will only be used if something is plugged into the Thunderbolt or USB4 ports, and are available for other use normally. Or you might want to use an internal video capture device or sound card, or a few other types of PCIe add-in cards that would take up chipset lanes.

Your motherboard's physical connections set the tone

The other thing to remember is that the length of a PCIe slot doesn't always equal the number of lanes that slot supports. Generally, the top full-length slot on any motherboard will support 16 PCIe lanes. But not every full-length PCIe slot will have electrical connections for x16, and if you look inside the slot or behind the motherboard, you might see pins most of the way along (x8) or partway (x4). The shortest PCIe slots are x1, as in the image above, and are used for Wi-Fi cards and other low-bandwidth add-in cards.

M.2 slots for NVMe SSDs generally support x4 PCIe lanes on newer platforms, but at launch they came with x2 support. And some Mini PCs might only connect a single PCIe lane on each M.2 slot. Remember that data transfer is only as good as your slowest link, which is the network link or sometimes the USB ports for most computers. It doesn't matter how many PCIe lanes of NVMe you can utilize if your Ethernet port is 1GbE, and even 2.5GbE could be easily saturated.

The days of multi-GPU are over

At least, for the consumer platforms

One of the main reasons I wanted lots of PCIe lanes back in the day was to run two or more graphics cards for better performance in games and number-crunching tasks. But multi-GPU is no longer supported on consumer platforms by either Nvidia or AMD. There is a case to be made for multiple GPUs when doing AI tasks, but then you'll want Threadripper or other HEDT systems to have enough physical PCIe slots to use multiple cards, and the correct PCIe bifurcation to be able to run those cards at their best performance.

Motherboard PCIe lanes do matter, but not as much as they used to

Consumer level motherboards have always been limited on PCIe lanes, but it didn't matter as much in the days before NVMe SSDs. And it's only natural to want the best performance from the components you selected, but I've got multiple different generations of hardware and PCIe versions running and I don't notice any differences in daily use unless I'm specifically running a benchmark that gives me a discrete score. What's more important is how your motherboard and CPU portion those PCIe lanes out, and unfortunately you're going to need to pony up for HEDT platforms if you want to use multiple PCIe devices at once.