diff --git a/src/single_window/render.h b/src/single_window/render.h
index 304df7d..898b017 100644
--- a/src/single_window/render.h
+++ b/src/single_window/render.h
@@ -15,6 +15,7 @@
 #include <mutex>
 #include <optional>
 #include <string>
+#include <unordered_map>
 
 #include "IconsFontAwesome6.h"
 #include "config_center.h"
@@ -269,7 +270,8 @@ class Render {
   std::unique_ptr<Thumbnail> thumbnail_;
 
   // recent connections
-  std::map<std::string, Thumbnail::RecentConnection> recent_connections_;
+  std::unordered_map<std::string, Thumbnail::RecentConnection>
+      recent_connections_;
   int recent_connection_image_width_ = 160;
   int recent_connection_image_height_ = 90;
   uint32_t recent_connection_image_save_time_ = 0;
diff --git a/src/single_window/thumbnail.cpp b/src/single_window/thumbnail.cpp
index c3ad6bc..99f8055 100644
--- a/src/single_window/thumbnail.cpp
+++ b/src/single_window/thumbnail.cpp
@@ -186,8 +186,8 @@ int Thumbnail::SaveToThumbnail(const char* yuv420p, int width, int height,
 
 int Thumbnail::LoadThumbnail(
     SDL_Renderer* renderer,
-    std::map<std::string, RecentConnection>& recent_connections, int* width,
-    int* height) {
+    std::unordered_map<std::string, RecentConnection>& recent_connections,
+    int* width, int* height) {
   for (auto& it : recent_connections) {
     if (it.second.texture != nullptr) {
       SDL_DestroyTexture(it.second.texture);
diff --git a/src/single_window/thumbnail.h b/src/single_window/thumbnail.h
index cf6b0ca..431a087 100644
--- a/src/single_window/thumbnail.h
+++ b/src/single_window/thumbnail.h
@@ -11,6 +11,7 @@
 
 #include <filesystem>
 #include <map>
+#include <unordered_map>
 #include <vector>
 
 class Thumbnail {
@@ -34,9 +35,10 @@ class Thumbnail {
                       const std::string& host_name,
                       const std::string& password);
 
-  int LoadThumbnail(SDL_Renderer* renderer,
-                    std::map<std::string, RecentConnection>& recent_connections,
-                    int* width, int* height);
+  int LoadThumbnail(
+      SDL_Renderer* renderer,
+      std::unordered_map<std::string, RecentConnection>& recent_connections,
+      int* width, int* height);
 
   int DeleteThumbnail(const std::string& filename_keyword);