Live session is a pure-RAM tmpfs overlay. Cinnamon takes ~2.5GB, nix packages take ~4GB — 6GB QEMU was too tight. 12GB gives comfortable headroom. Real XPS 9700 (32GB) already works fine. - tests/launch-live-qemu.sh: dedicated QEMU launcher, RAM_MB=12288 - Makefile: 'make live-qemu' target