diff --git a/DECISIONS.md b/DECISIONS.md
index 74978ea..09c3e9c 100644
--- a/DECISIONS.md
+++ b/DECISIONS.md
@@ -1,5 +1,25 @@
 # Decisions
 
+## 2026-08-24 – power-profiles-daemon replaces auto-cpufreq
+
+- **Who**: Dominik, ClaudeCode
+- **Why**: auto-cpufreq arrived a day earlier as the backend of the quickshell CpuGov
+  widget, not because it fits the hardware. Upstream calls it a laptop tool and points
+  AMD users at `amd_pstate.enable=0`, while the kernel documents that amd-pstate in
+  active mode ignores the requested performance level and reads only the minimum,
+  maximum and EPP registers — so the governor auto-cpufreq switches decides nothing.
+- **Tradeoffs**: ppd writes those registers (`ppd-driver-amd-pstate.c`) and the ACPI
+  `platform_profile`, and its polkit policy allows the active session to switch
+  profiles without pkexec. Given up is the load-dependent automatic: ppd has three
+  fixed profiles and leaves reacting to the firmware. The module lives in
+  `modules/services.nix`, so the testvm gets it too — there ppd finds no driver and
+  falls back to `ppd-driver-placeholder.c`, which touches no hardware, whereas
+  auto-cpufreq was a daemon polling sysfs that a virtio guest does not have. The
+  NixOS module asserts against auto-cpufreq, so a leftover elsewhere fails evaluation
+  rather than running two daemons at one knob.
+- **How**: `services.power-profiles-daemon.enable` in `modules/services.nix`. The widget
+  itself lives in the moonarch tree this flake deploys from and switched with it.
+
 ## 2026-08-20 – Input denoising was deployed to a path PipeWire never reads
 
 - **Who**: Dominik, ClaudeCode
diff --git a/modules/services.nix b/modules/services.nix
index 1dab3c5..2db6629 100644
--- a/modules/services.nix
+++ b/modules/services.nix
@@ -20,7 +20,11 @@
   services.upower.enable = true;
   services.gvfs.enable = true;
   services.fwupd.enable = true;
-  services.auto-cpufreq.enable = true;
+  # power-profiles-daemon over auto-cpufreq: on amd-pstate in active mode the
+  # platform decides the frequency from the min/max and EPP registers alone, so
+  # the governor is the wrong knob. ppd writes EPP and the ACPI platform_profile;
+  # where neither exists it falls back to a driver that touches no hardware.
+  services.power-profiles-daemon.enable = true;
 
   # --- Firewall, replaces the ufw calls in post-install.sh ---
   networking.firewall.enable = true;