diff --git a/CMakeLists.txt b/CMakeLists.txt
index c9de8618..e53df168 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -187,9 +187,16 @@ target_compile_options(mimalloc-test-stress PRIVATE ${mi_cflags})
 target_include_directories(mimalloc-test-stress PRIVATE include)
 target_link_libraries(mimalloc-test-stress PRIVATE mimalloc-static)
 
+add_executable(mimalloc-test-map-frag test/test-leak.cpp)
+target_compile_definitions(mimalloc-test-map-frag PRIVATE ${mi_defines})
+target_compile_options(mimalloc-test-map-frag PRIVATE ${mi_cflags})
+target_include_directories(mimalloc-test-map-frag PRIVATE include)
+target_link_libraries(mimalloc-test-map-frag PRIVATE mimalloc-static)
+
 enable_testing()
 add_test(test_api, mimalloc-test-api)
 add_test(test_stress, mimalloc-test-stress)
+add_test(test_map_frag, mimalloc-test-map-frag)
 
 # -----------------------------------------------------------------------------
 # Set override properties
diff --git a/ide/vs2017/mimalloc-test-stress.vcxproj b/ide/vs2017/mimalloc-test-stress.vcxproj
index 5ef92d86..357d3985 100644
--- a/ide/vs2017/mimalloc-test-stress.vcxproj
+++ b/ide/vs2017/mimalloc-test-stress.vcxproj
@@ -89,6 +89,7 @@
       <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>..\..\include</AdditionalIncludeDirectories>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -101,6 +102,7 @@
       <SDLCheck>true</SDLCheck>
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>..\..\include</AdditionalIncludeDirectories>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -116,6 +118,7 @@
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>..\..\include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>%(PreprocessorDefinitions);NDEBUG</PreprocessorDefinitions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -133,6 +136,7 @@
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>..\..\include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>%(PreprocessorDefinitions);NDEBUG</PreprocessorDefinitions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -141,7 +145,12 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="..\..\test\test-leak.cpp" />
     <ClCompile Include="..\..\test\test-stress.c">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|x64'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
@@ -152,4 +161,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/ide/vs2017/mimalloc-test-stress.vcxproj.filters b/ide/vs2017/mimalloc-test-stress.vcxproj.filters
index b857ea52..39162b4e 100644
--- a/ide/vs2017/mimalloc-test-stress.vcxproj.filters
+++ b/ide/vs2017/mimalloc-test-stress.vcxproj.filters
@@ -18,5 +18,8 @@
     <ClCompile Include="..\..\test\test-stress.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\test\test-leak.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/memory.c b/src/memory.c
index 3a881893..c49b00a9 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -314,10 +314,10 @@ void _mi_mem_free(void* p, size_t size, size_t id, mi_stats_t* stats) {
     // reset: 10x slowdown on malloc-large, decommit: 17x slowdown on malloc-large
     if (!mi_option_is_enabled(mi_option_large_os_pages)) {
       if (mi_option_is_enabled(mi_option_eager_region_commit)) {
-        _mi_os_reset(p, size, stats);      // 10x slowdown on malloc-large
+        //_mi_os_reset(p, size, stats);      // 10x slowdown on malloc-large
       }
       else {      
-        _mi_os_decommit(p, size, stats);  // 17x slowdown on malloc-large
+        //_mi_os_decommit(p, size, stats);  // 17x slowdown on malloc-large
       }
     }
 
diff --git a/src/options.c b/src/options.c
index 0e0b0556..9f408874 100644
--- a/src/options.c
+++ b/src/options.c
@@ -34,8 +34,8 @@ typedef struct mi_option_desc_s {
 static mi_option_desc_t options[_mi_option_last] = {
   { 0, UNINIT, "page_reset" },
   { 0, UNINIT, "cache_reset" },
-  { 0, UNINIT, "eager_commit" },     
-  { 0, UNINIT, "eager_region_commit" },
+  { 1, UNINIT, "eager_commit" },     
+  { 1, UNINIT, "eager_region_commit" },
   { 0, UNINIT, "large_os_pages" },   // use large OS pages, use only with eager commit to prevent fragmentation of VMA's
   { 0, UNINIT, "reset_decommits" },
   { 0, UNINIT, "reset_discards" },