Index: src/kitemviews/kfileitemmodel.h
===================================================================
--- src/kitemviews/kfileitemmodel.h
+++ src/kitemviews/kfileitemmodel.h
@@ -355,6 +355,11 @@
 
     QHash<QByteArray, QVariant> retrieveData(const KFileItem& item, const ItemData* parent) const;
 
+    /**
+     * @return True if we need role values to QString for sorting.
+     */
+    static bool stringRolesTrue(const RoleType roleType);
+
     /**
      * @return True if \a a has a KFileItem whose text is 'less than' the one
      *         of \a b according to QString::operator<(const QString&).
@@ -504,6 +509,22 @@
     friend class DolphinPart;                  // Accesses m_dirLister
 };
 
+inline bool KFileItemModel::stringRolesTrue(RoleType roleType)
+{
+    return (roleType == TypeRole ||
+            roleType == TagsRole ||
+            roleType == CommentRole ||
+            roleType == TitleRole ||
+            roleType == ArtistRole ||
+            roleType == GenreRole ||
+            roleType == AlbumRole ||
+            roleType == PathRole ||
+            roleType == DestinationRole ||
+            roleType == OriginUrlRole ||
+            roleType == OwnerRole ||
+            roleType == GroupRole);
+}
+
 inline bool KFileItemModel::nameLessThan(const ItemData* a, const ItemData* b)
 {
     return a->item.text() < b->item.text();
Index: src/kitemviews/kfileitemmodel.cpp
===================================================================
--- src/kitemviews/kfileitemmodel.cpp
+++ src/kitemviews/kfileitemmodel.cpp
@@ -1187,12 +1187,20 @@
     m_groups.clear();
     prepareItemsForSorting(newItems);
 
-    if (m_sortRole == NameRole && m_naturalSorting) {
-        // Natural sorting of items can be very slow. However, it becomes much
-        // faster if the input sequence is already mostly sorted. Therefore, we
-        // first sort 'newItems' according to the QStrings returned by
-        // KFileItem::text() using QString::operator<(), which is quite fast.
-        parallelMergeSort(newItems.begin(), newItems.end(), nameLessThan, QThread::idealThreadCount());
+    // Natural sorting of items can be very slow. However, it becomes much faster
+    // if the input sequence is already mostly sorted. Therefore, we first sort
+    // 'newItems' according to the QStrings using QString::operator<(), which is quite fast.
+    if (m_naturalSorting) {
+        if (m_sortRole == NameRole) {
+            parallelMergeSort(newItems.begin(), newItems.end(), nameLessThan, QThread::idealThreadCount());
+        } else if (stringRolesTrue(m_sortRole)) {
+            auto lambdaLessThan = [&] (const KFileItemModel::ItemData* a, const KFileItemModel::ItemData* b)
+            {
+                const QByteArray role = roleForType(m_sortRole);
+                return a->values.value(role).toString() < b->values.value(role).toString();
+            };
+            parallelMergeSort(newItems.begin(), newItems.end(), lambdaLessThan, QThread::idealThreadCount());
+        }
     }
 
     sort(newItems.begin(), newItems.end());
@@ -1726,8 +1734,8 @@
         return lessThan(a, b, m_collator);
     };
 
-    if (m_sortRole == NameRole) {
-        // Sorting by name can be expensive, in particular if natural sorting is
+    if (m_sortRole == NameRole || stringRolesTrue(m_sortRole)) {
+        // Sorting by string can be expensive, in particular if natural sorting is
         // enabled. Use all CPU cores to speed up the sorting process.
         static const int numberOfThreads = QThread::idealThreadCount();
         parallelMergeSort(begin, end, lambdaLessThan, numberOfThreads);
@@ -1827,6 +1835,31 @@
         break;
     }
 
+    case TypeRole:
+    case TagsRole:
+    case CommentRole:
+    case TitleRole:
+    case ArtistRole:
+    case GenreRole:
+    case AlbumRole:
+    case PathRole:
+    case DestinationRole:
+    case OriginUrlRole:
+    case OwnerRole:
+    case GroupRole: {
+        const QByteArray role = roleForType(m_sortRole);
+        const QString roleValueA = a->values.value(role).toString();
+        const QString roleValueB = b->values.value(role).toString();
+        if (!roleValueA.isEmpty() && roleValueB.isEmpty()) {
+            result = -1;
+        } else if (roleValueA.isEmpty() && !roleValueB.isEmpty()) {
+            result = +1;
+        } else {
+            result = stringCompare(roleValueA, roleValueB, collator);
+        }
+        break;
+    }
+
     default: {
         const QByteArray role = roleForType(m_sortRole);
         const QString roleValueA = a->values.value(role).toString();