diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Icon.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Icon.Windows.cs
index dc25bdf08d11c..68689fff1bebb 100644
--- a/src/libraries/System.Drawing.Common/src/System/Drawing/Icon.Windows.cs
+++ b/src/libraries/System.Drawing.Common/src/System/Drawing/Icon.Windows.cs
@@ -664,32 +664,23 @@ public void Save(Stream outputStream)
             }
         }
 
-        private void CopyBitmapData(BitmapData sourceData, BitmapData targetData)
+        private unsafe void CopyBitmapData(BitmapData sourceData, BitmapData targetData)
         {
-            int offsetSrc = 0;
-            int offsetDest = 0;
+            byte* srcPtr = (byte*)sourceData.Scan0;
+            byte* destPtr = (byte*)targetData.Scan0;
 
             Debug.Assert(sourceData.Height == targetData.Height, "Unexpected height. How did this happen?");
+            int height = Math.Min(sourceData.Height, targetData.Height);
+            long bytesToCopyEachIter = Math.Abs(targetData.Stride);
 
-            for (int i = 0; i < Math.Min(sourceData.Height, targetData.Height); i++)
+            for (int i = 0; i < height; i++)
             {
-                IntPtr srcPtr, destPtr;
-                if (IntPtr.Size == 4)
-                {
-                    srcPtr = new IntPtr(sourceData.Scan0.ToInt32() + offsetSrc);
-                    destPtr = new IntPtr(targetData.Scan0.ToInt32() + offsetDest);
-                }
-                else
-                {
-                    srcPtr = new IntPtr(sourceData.Scan0.ToInt64() + offsetSrc);
-                    destPtr = new IntPtr(targetData.Scan0.ToInt64() + offsetDest);
-                }
-
-                UnsafeNativeMethods.CopyMemory(new HandleRef(this, destPtr), new HandleRef(this, srcPtr), Math.Abs(targetData.Stride));
-
-                offsetSrc += sourceData.Stride;
-                offsetDest += targetData.Stride;
+                Buffer.MemoryCopy(srcPtr, destPtr, bytesToCopyEachIter, bytesToCopyEachIter);
+                srcPtr += sourceData.Stride;
+                destPtr += targetData.Stride;
             }
+
+            GC.KeepAlive(this); // finalizer mustn't deallocate data blobs while this method is running
         }
 
         private static bool BitmapHasAlpha(BitmapData bmpData)
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/UnsafeNativeMethods.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/UnsafeNativeMethods.cs
index 14093caee6f5e..00aa1233af043 100644
--- a/src/libraries/System.Drawing.Common/src/System/Drawing/UnsafeNativeMethods.cs
+++ b/src/libraries/System.Drawing.Common/src/System/Drawing/UnsafeNativeMethods.cs
@@ -7,9 +7,6 @@ namespace System.Drawing
 {
     internal class UnsafeNativeMethods
     {
-        [DllImport(ExternDll.Kernel32, SetLastError = true, ExactSpelling = true, EntryPoint = "RtlMoveMemory")]
-        public static extern void CopyMemory(HandleRef destData, HandleRef srcData, int size);
-
         [DllImport(ExternDll.Kernel32, SetLastError = true)]
         public static extern int GetSystemDefaultLCID();