i5-4590 with 4GB of RAM running Windows 10—is there a worse setup that can still run it?

Hello,

It can indeed get significantly worse. Just recently, purely for testing purposes, I successfully installed and ran Windows 10 on a 2nd generation Intel Core i3 system equipped with only 2 GB of RAM. The experience was far from pleasant, everything felt extremely sluggish, with long delays on almost every operation.

Interestingly, in the early days of Windows 10 (around 2015–2017), the same low-end hardware was still reasonably responsive and usable for basic tasks. Over the years, the increasing resource demands have made such older systems much less practical.

In my opinion, on this class of legacy hardware the HDD is usually the primary bottleneck. Upgrading to even a modest SATA SSD often transforms the user experience, making these otherwise very weak systems surprisingly usable again for light workloads.