I replaced my 2500K a couple years ago using the cheapest AMD components I could find. The main improvements were mostly in the chipset/motherboard:
- The PCIe 2.0 lanes on the old CPU were throttling my NVMe drive to 1GB/sec transfer rates.
- USB3 compatibility and USB power delivery were vastly more reliable. My old 2500K ASUS motherboard couldn't power a Lenovo VR headset for example, and plugging too many things into my USB hub would cause device dropouts.
- Some improvement in either DDR4 memory bandwidth or latency fixed occasional loading stalls I'd see in games when transitioning to new areas. Even with the same GPU, before the upgrade games would lock up for about half a second sometimes and then go back to running in 60fps.
- The PCIe 2.0 lanes on the old CPU were throttling my NVMe drive to 1GB/sec transfer rates.
- USB3 compatibility and USB power delivery were vastly more reliable. My old 2500K ASUS motherboard couldn't power a Lenovo VR headset for example, and plugging too many things into my USB hub would cause device dropouts.
- Some improvement in either DDR4 memory bandwidth or latency fixed occasional loading stalls I'd see in games when transitioning to new areas. Even with the same GPU, before the upgrade games would lock up for about half a second sometimes and then go back to running in 60fps.