diff --git a/audit/internal/platform/benchmark.go b/audit/internal/platform/benchmark.go
index 9533315..814ec25 100644
--- a/audit/internal/platform/benchmark.go
+++ b/audit/internal/platform/benchmark.go
@@ -705,8 +705,14 @@ func scoreBenchmarkGPUResult(gpu BenchmarkGPUResult) BenchmarkScorecard {
 			score.ComputeScore += precision.TeraOpsPerSec
 		}
 	}
-	if gpu.PowerLimitW > 0 {
-		score.PowerSustainScore = math.Min(100, (gpu.Steady.AvgPowerW/gpu.PowerLimitW)*100)
+	// Use default power limit for sustain score so a manually reduced limit
+	// does not inflate the score. Fall back to enforced limit if default unknown.
+	referencePowerW := gpu.DefaultPowerLimitW
+	if referencePowerW <= 0 {
+		referencePowerW = gpu.PowerLimitW
+	}
+	if referencePowerW > 0 {
+		score.PowerSustainScore = math.Min(100, (gpu.Steady.AvgPowerW/referencePowerW)*100)
 	}
 	runtimeUS := math.Max(1, gpu.Steady.DurationSec*1e6)
 	thermalRatio := float64(gpu.Throttle.HWThermalSlowdownUS+gpu.Throttle.SWThermalSlowdownUS) / runtimeUS