DDR5 heat isn't the problem in mini-ITX builds.

Not really. The heat from DDR5 is a non-issue for thermal throttling in most mini-ITX cases.

Yes, DDR5 runs hotter than DDR4 — higher voltage and higher speeds. But the thermal output of your memory sticks is tiny compared to what your CPU and GPU are dumping into that small case. A modern mini-ITX build’s real heat problems come from poor airflow, small CPU coolers, and the GPU’s hot backplate radiating onto the RAM. Even if your DDR5 hits 55-60°C, most modules don’t throttle until 85-95°C, and the only time I’ve seen that happen is with extreme overclocking or zero airflow.

If you’re worried, get a case with a top exhaust fan near the RAM slots, or use a low-profile air cooler that directs airflow over the sticks. But don’t swap to DDR4 just for thermal concerns. You’ll lose memory bandwidth and future-proofing for maybe a 2-3°C difference in RAM temps — and your CPU will still be the bottleneck.

Worry about your CPU cooler first.