diff --git a/graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java b/graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java
index 5f2ec5e99f..9b137e1fb2 100644
--- a/graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java
+++ b/graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java
@@ -1021,10 +1021,10 @@ private static void applyThroughputJitPreset(Map<String, String> polyglotOptions
     }
 
     private static void applyRaisedJitThresholds(Map<String, String> polyglotOptions) {
-        polyglotOptions.put("engine.FirstTierCompilationThreshold", "10000");
-        polyglotOptions.put("engine.LastTierCompilationThreshold", "100000");
+        polyglotOptions.put("engine.FirstTierCompilationThreshold", "2000");
+        polyglotOptions.put("engine.LastTierCompilationThreshold", "50000");
         polyglotOptions.put("engine.OSRCompilationThreshold", "200704");
-        polyglotOptions.put("engine.SingleTierCompilationThreshold", "100000");
+        polyglotOptions.put("engine.SingleTierCompilationThreshold", "10000");
     }
 
     private static String toAbsolutePath(String executable) {
diff --git a/graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Python3Core.java b/graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Python3Core.java
index 17b5fec576..72124281d5 100644
--- a/graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Python3Core.java
+++ b/graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Python3Core.java
@@ -1051,14 +1051,12 @@ private void initializePython3Core(TruffleString coreHome) {
     }
 
     private void initializeWindowsCoreFiles(TruffleString coreHome) {
-        if (PythonLanguage.getPythonOS() == PythonOS.PLATFORM_WIN32) {
-            assert !ImageInfo.inImageBuildtimeCode();
-            loadFile(toTruffleStringUncached("_nt"), coreHome);
-            loadFile(toTruffleStringUncached("_winapi"), toTruffleStringUncached("modules/_winapi"), coreHome);
-            loadFile(toTruffleStringUncached("_overlapped"), toTruffleStringUncached("modules/_overlapped"), coreHome);
-            loadFile(toTruffleStringUncached("winreg"), toTruffleStringUncached("modules/winreg"), coreHome);
-            loadFile(toTruffleStringUncached("_winreg"), toTruffleStringUncached("modules/_winreg"), coreHome);
-        }
+        assert !ImageInfo.inImageBuildtimeCode();
+        loadFile(toTruffleStringUncached("_nt"), coreHome);
+        loadFile(toTruffleStringUncached("_winapi"), toTruffleStringUncached("modules/_winapi"), coreHome);
+        loadFile(toTruffleStringUncached("_overlapped"), toTruffleStringUncached("modules/_overlapped"), coreHome);
+        loadFile(toTruffleStringUncached("winreg"), toTruffleStringUncached("modules/winreg"), coreHome);
+        loadFile(toTruffleStringUncached("_winreg"), toTruffleStringUncached("modules/_winreg"), coreHome);
     }
 
     /**
@@ -1069,7 +1067,9 @@ private void initializeWindowsCoreFiles(TruffleString coreHome) {
     public final void postInitialize(Env env) {
         if (!env.isPreInitialization()) {
             initialized = false;
-            initializeWindowsCoreFiles(getContext().getCoreHomeOrFail());
+            if (PythonLanguage.getPythonOS() == PythonOS.PLATFORM_WIN32) {
+                initializeWindowsCoreFiles(getContext().getCoreHomeOrFail());
+            }
 
             for (PythonBuiltins builtin : builtins) {
                 if (builtin.needsPostInitialize()) {