My current office desktop and home desktop are now more than five years old (although they've had some storage tuneups since then), so I've been looking at PC hardware off and on. As it happens, PC desktop motherboards that have the features I'd like also not infrequently include extra features that I don't need, such as built in wifi connectivity. I'm somewhat of a hardware minimalist so in the past I've reflexively attempted to avoid these features. The obvious reason to do this is that they tend to increase the cost. But lately it's struck me that there's another reason to want a desktop PC motherboard without extra features, and that is PCIe lanes.

Processors (CPUs) and motherboard chipsets only have so many PCIe lanes in total, partly because supporting more PCIe lanes is one of those product features that both Intel and AMD use to segment the market. This matters because days, almost everything built into a PC motherboard is actually implemented as a PCIe device, which means that it normally consumes some number of those PCIe lanes. The more built in devices your motherboard has, the more PCIe lanes they consume out of the total ones available, which can cut down on other built in devices and also on connectivity you want, such as NVMe drives and physical PCIe card slots. Physical PCIe slots can already have peculiar limitations on which ones can be used together, which has the effect of reducing the total PCIe lanes they consume, but you generally can't play very many of these games with built in hardware.

(You can play some games; on my home desktop, the motherboard's second NVMe slot shares two PCIe lanes with some of my SATA ports. If I want to run the NVMe drive with x4 PCIe lanes instead of x2, I can only have four SATA ports instead of six.)

Of course, all of this is academic if you can only find the motherboard features you want on higher end motherboards that also include these extra features. Provided that there aren't any surprise limitations that affect things you're going to use right away, you (I) just get to live with whatever limitations and constraints on PCIe lane usage you get, or you have to drop some features you want. This is where you have to read motherboard descriptions quite carefully, including all of the footnotes, and perhaps even consult their manuals.

(What features I want is another question, and there are tradeoffs I could make and may have to.)

Fortunately (given the growth of things like NVMe drives), the number of PCIe lanes available from CPUs and chipsets has been going up over time, as has their speed. However I suspect that we're always going to see Intel and AMD differentiate their server processors from their desktop processors partly by the number of PCIe lanes available, with the 'desktop' processors having the smaller number. My impression is that AMD desktop CPUs have more CPU PCIe lanes than Intel desktop CPUs and also I believe more chipset PCIe lanes, but Intel is potentially ahead on PCIe bandwidth between the chipset and the CPU (and thus between chipset devices and RAM, which has to go through the CPU). Whether you'll ever stress the CPU to chipset bandwidth that hard is another question.