--- a/app/src/main/java/com/kazeia/stt/WhisperHybridEngine.kt
+++ b/app/src/main/java/com/kazeia/stt/WhisperHybridEngine.kt
@@ -98,8 +98,15 @@ class WhisperHybridEngine(
                         val htpPath = "$nativeLibDir/libQnnHtp.so"
                         nlog("Loading HfWhisper encoder (QNN NPU)...")
                         val t0 = System.currentTimeMillis()
                         val encOpts = OrtSession.SessionOptions()
-                        encOpts.addQnn(mapOf("backend_path" to htpPath))
+                        encOpts.addQnn(mapOf(
+                            "backend_path"              to htpPath,
+                            "htp_performance_mode"      to "burst",        // NPU freq max (vs default = balanced)
+                            "htp_arch"                  to "79",           // SM8750 = SD8 Elite V79
+                            "enable_htp_fp16_precision" to "1",            // NPU fp16 natif
+                        ))
+                        encOpts.setOptimizationLevel(
+                            OrtSession.SessionOptions.OptLevel.ALL_OPT)
                         hfEncoderSession = ortEnv!!.createSession(hfEncPath, encOpts)
                         val encMs = System.currentTimeMillis() - t0
                         nlog("HfEncoder NPU loaded: ${encMs}ms")

                         nlog("Loading HfWhisper decoder (QNN NPU)...")
                         val t1 = System.currentTimeMillis()
                         val decOpts = OrtSession.SessionOptions()
-                        decOpts.addQnn(mapOf("backend_path" to htpPath))
+                        decOpts.addQnn(mapOf(
+                            "backend_path"              to htpPath,
+                            "htp_performance_mode"      to "burst",
+                            "htp_arch"                  to "79",
+                            "enable_htp_fp16_precision" to "1",
+                        ))
+                        decOpts.setOptimizationLevel(
+                            OrtSession.SessionOptions.OptLevel.ALL_OPT)
                         hfDecoderSession = ortEnv!!.createSession(hfDecPath, decOpts)
                         val decMs = System.currentTimeMillis() - t1
                         nlog("HfDecoder NPU loaded: ${decMs}ms")
@@ -130,9 +137,15 @@ class WhisperHybridEngine(
                 if (!useHfModels) {
                     val encNpuPath = "$path/encoder_npu/model.onnx"
                     if (File(encNpuPath).exists()) {
                         try {
                             val encOpts = OrtSession.SessionOptions()
-                            encOpts.addQnn(mapOf("backend_path" to "$nativeLibDir/libQnnHtp.so"))
+                            encOpts.addQnn(mapOf(
+                                "backend_path"              to "$nativeLibDir/libQnnHtp.so",
+                                "htp_performance_mode"      to "burst",
+                                "htp_arch"                  to "79",
+                                "enable_htp_fp16_precision" to "1",
+                            ))
+                            encOpts.setOptimizationLevel(
+                                OrtSession.SessionOptions.OptLevel.ALL_OPT)
                             nlog("Loading encoder (QNN NPU)...")
                             val t0 = System.currentTimeMillis()
                             encoderSession = ortEnv!!.createSession(encNpuPath, encOpts)