diff --git a/src/os/win32/sigar_os.h b/src/os/win32/sigar_os.h
index fd060e39..87de29ca 100644
--- a/src/os/win32/sigar_os.h
+++ b/src/os/win32/sigar_os.h
@@ -170,10 +170,28 @@ typedef enum {
     SC_STATUS_PROCESS_INFO = 0
 } SC_STATUS_TYPE;
 
+typedef struct _PERFORMANCE_INFORMATION {
+    DWORD  cb;
+    SIZE_T CommitTotal;
+    SIZE_T CommitLimit;
+    SIZE_T CommitPeak;
+    SIZE_T PhysicalTotal;
+    SIZE_T PhysicalAvailable;
+    SIZE_T SystemCache;
+    SIZE_T KernelTotal;
+    SIZE_T KernelPaged;
+    SIZE_T KernelNonpaged;
+    SIZE_T PageSize;
+    DWORD  HandleCount;
+    DWORD  ProcessCount;
+    DWORD  ThreadCount;
+} PERFORMANCE_INFORMATION, *PPERFORMANCE_INFORMATION;
+
 #ifndef ERROR_DATATYPE_MISMATCH
 #define ERROR_DATATYPE_MISMATCH 1629L
 #endif
-
+#else
+#include <psapi.h>
 #endif /* _MSC_VER */
 
 #include <iprtrmib.h>
@@ -437,6 +455,8 @@ typedef BOOL (CALLBACK *psapi_enum_processes)(DWORD *,
                                               DWORD,
                                               DWORD *);
 
+typedef BOOL (CALLBACK *psapi_get_perf_info)(PPERFORMANCE_INFORMATION, DWORD);
+
 /* winsta.dll */
 typedef BOOLEAN (CALLBACK *winsta_query_info)(HANDLE,
                                               ULONG,
@@ -513,6 +533,7 @@ typedef struct {
     SIGAR_DLLFUNC(psapi, enum_modules);
     SIGAR_DLLFUNC(psapi, enum_processes);
     SIGAR_DLLFUNC(psapi, get_module_name);
+    SIGAR_DLLFUNC(psapi, get_perf_info);
 
     sigar_dll_func_t end;
 } sigar_psapi_t;
diff --git a/src/os/win32/win32_sigar.c b/src/os/win32/win32_sigar.c
index d029d4d0..5f2878bd 100755
--- a/src/os/win32/win32_sigar.c
+++ b/src/os/win32/win32_sigar.c
@@ -341,6 +341,7 @@ static sigar_psapi_t sigar_psapi = {
     { "EnumProcessModules", NULL },
     { "EnumProcesses", NULL },
     { "GetModuleFileNameExA", NULL },
+    { "GetPerformanceInfo", NULL },
     { NULL, NULL }
 };
 
@@ -630,9 +631,14 @@ char *sigar_os_error_string(sigar_t *sigar, int err)
 #define sigar_GlobalMemoryStatusEx \
     sigar->kernel.memory_status.func
 
+#define sigar_GetPerformanceInfo \
+    sigar->psapi.get_perf_info.func
+
 SIGAR_DECLARE(int) sigar_mem_get(sigar_t *sigar, sigar_mem_t *mem)
 {
+    sigar_uint64_t kern = 0;
     DLLMOD_INIT(kernel, TRUE);
+    DLLMOD_INIT(psapi, FALSE);
 
     if (sigar_GlobalMemoryStatusEx) {
         MEMORYSTATUSEX memstat;
@@ -645,6 +651,14 @@ SIGAR_DECLARE(int) sigar_mem_get(sigar_t *sigar, sigar_mem_t *mem)
 
         mem->total = memstat.ullTotalPhys;
         mem->free  = memstat.ullAvailPhys;
+
+        if (sigar_GetPerformanceInfo) {
+            PERFORMANCE_INFORMATION info;
+            if (sigar_GetPerformanceInfo(&info, sizeof(info))) {
+                kern = info.SystemCache;
+                kern *= sigar->pagesize;
+            }
+        }
     }
     else {
         MEMORYSTATUS memstat;
@@ -655,8 +669,8 @@ SIGAR_DECLARE(int) sigar_mem_get(sigar_t *sigar, sigar_mem_t *mem)
 
     mem->used = mem->total - mem->free;
 
-    mem->actual_free = mem->free;
-    mem->actual_used = mem->used;
+    mem->actual_free = mem->free + kern;
+    mem->actual_used = mem->used - kern;
 
     sigar_mem_calc_ram(sigar, mem);