For fun, installed win11 on my X300.

[piledriver]

For fun, I installed win11 on my x300.
(after making backup on the 2TBs of spinning rust in the ultrabay, I'm primarily a Linux user).

I did this with a rufus generated usb, files copied back onto a directory on the desktop for an upgrade install rather than nuking things from orbit, as Win10 worked fine.
(rufus will offer some uptions to check before it creates the USB stick)

X300s were not remotely fast when new, with the ultra low voltage 1.2GHz core2 duo... but with a modern-ish ssd and 8gb ram it seems to run win11 just fine.
Some things seem a little faster vs. win10, maybe half a step slower here and there.

Not bad for the old girl being new in 2009.

BTW, don't install Windows 11 on spinning rust, an SSD should really be the mandatory requirement.
My "new to me" x260 with 32gb ram and a WD 1TB HDD ran win10 great, but win11 filled it with molasses... unusable. swapped a spare SATA ssd in, voila! win 11 installed in like 10 minutes, and seems to run faster than some new hardware. Absolutely flies with the new NVME 2TB P41.

Almost seems intentional, as I cant think of why win11 would need to hit the drive like that, its really only win10 with the furniture rearranged.