The headline differences
DDR5 launched at 4800 MT/s and is shipping today at 5600 MT/s in mainstream desktop and laptop configurations - roughly 1.4-1.7x the bandwidth of DDR4 at 3200 MT/s. Operating voltage drops from 1.2 V (DDR4) to 1.1 V (DDR5), and power management moves from the motherboard onto the module itself via a small on-board PMIC.
Where the upgrade pays back
Workloads that move large blocks through memory - video editing, 3D rendering, large-model inference, big in-memory databases, even modern game engines at high resolutions - benefit measurably from the extra bandwidth. Office and browsing workloads will not feel the change.
Where it doesn't
DDR5 modules require a DDR5-capable motherboard. Intel 12th-gen+ and AMD Ryzen 7000 series support it; older platforms do not, and DDR5 is physically keyed differently from DDR4 so they cannot share a slot. If your platform is DDR4-only, the upgrade is a full system rebuild, not a memory swap.
A practical decision rule
If you're building today, default to DDR5 - the price gap has closed and you'll get more useful life out of the system. If you have a working DDR4 platform with a workload that isn't memory-bandwidth-bound, sit on it and upgrade at your next platform refresh.