Go with single mode only for new installs.

Biggest install cost is labour. The cable and optics are cheap now, and with the future (200Gbps+) being multiple wavelengths in parallel[1], we’ve pretty much hit the end of the road for MMF.

[1] https://www.tiafotc.org/ieee-802-3-ethernet-standards-update...

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sekh60 3 hours ago | parent | next [-]

This is the correct answer, always single mode. It's been the most future proof to date, people just keep figuring out how to cram more and more wavelengths into it.

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simoncion 5 hours ago | parent | prev [-]

> Biggest install cost is labour.

Okay? If I had to run cabling through a wall, I'd make sure the guy sets it up so that I can use the cable he installs to pull new later. My time's free when I'm doing something that I don't mind doing, and I don't mind easy cable pulls.

> ...(200Gbps+)...

Don't you need 16x PCIe 4.0 for those guys? With everything other than workstation and server boards having exactly one 16x slot, you're "never" hooking that up to a gaming PC.

	▲	bigfatkitten an hour ago \| parent [-]
		MMF cable is quite a bit more expensive than SMF. The cost savings used to be in optics, but that distinction has fallen away. Everyone needs a hobby, so if you want to replace the cable later on nobody’s going to stop you. There was a time when we couldn’t buy a PC that could saturate 1Gbps ethernet, and that time wasn’t that long ago. Your cabling plant will outlive any hardware you buy today.