diff --git a/Source/Core/UICommon/GameFileCache.cpp b/Source/Core/UICommon/GameFileCache.cpp
@@ -0,0 +1,235 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "UICommon/GameFileCache.h"
+
+#include <algorithm>
+#include <cstddef>
+#include <functional>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <unordered_set>
+#include <vector>
+
+#include "Common/ChunkFile.h"
+#include "Common/CommonTypes.h"
+#include "Common/File.h"
+#include "Common/FileSearch.h"
+#include "Common/FileUtil.h"
+
+#include "Core/TitleDatabase.h"
+
+#include "DiscIO/DirectoryBlob.h"
+
+#include "UICommon/GameFile.h"
+
+namespace UICommon
+{
+static constexpr u32 CACHE_REVISION = 7;  // Last changed in PR 6281
+
+std::vector<std::string> FindAllGamePaths(const std::vector<std::string>& directories_to_scan,
+                                          bool recursive_scan)
+{
+  static const std::vector<std::string> search_extensions = {
+      ".gcm", ".tgc", ".iso", ".ciso", ".gcz", ".wbfs", ".wad", ".dol", ".elf"};
+
+  // TODO: We could process paths iteratively as they are found
+  return Common::DoFileSearch(directories_to_scan, search_extensions, recursive_scan);
+}
+
+void GameFileCache::ForEach(std::function<void(const std::shared_ptr<const GameFile>&)> f) const
+{
+  for (const std::shared_ptr<const GameFile>& item : m_cached_files)
+    f(item);
+}
+
+void GameFileCache::Clear()
+{
+  m_cached_files.clear();
+}
+
+std::shared_ptr<const GameFile> GameFileCache::AddOrGet(const std::string& path,
+                                                        bool* cache_changed,
+                                                        const Core::TitleDatabase& title_database)
+{
+  auto it = std::find_if(
+      m_cached_files.begin(), m_cached_files.end(),
+      [&path](const std::shared_ptr<GameFile>& file) { return file->GetFilePath() == path; });
+  const bool found = it != m_cached_files.cend();
+  if (!found)
+    m_cached_files.emplace_back(std::make_shared<GameFile>(path));
+  std::shared_ptr<GameFile>& result = found ? *it : m_cached_files.back();
+  if (UpdateAdditionalMetadata(&result, title_database) || !found)
+    *cache_changed = true;
+
+  return result;
+}
+
+bool GameFileCache::Update(const std::vector<std::string>& all_game_paths)
+{
+  // Copy game paths into a set, except ones that match DiscIO::ShouldHideFromGameList.
+  // TODO: Prevent DoFileSearch from looking inside /files/ directories of DirectoryBlobs at all?
+  // TODO: Make DoFileSearch support filter predicates so we don't have remove things afterwards?
+  std::unordered_set<std::string> game_paths;
+  game_paths.reserve(all_game_paths.size());
+  for (const std::string& path : all_game_paths)
+  {
+    if (!DiscIO::ShouldHideFromGameList(path))
+      game_paths.insert(path);
+  }
+
+  bool cache_changed = false;
+
+  // Delete paths that aren't in game_paths from m_cached_files,
+  // while simultaneously deleting paths that aren't in m_cached_files from game_paths.
+  // For the sake of speed, we don't care about maintaining the order of m_cached_files.
+  {
+    auto it = m_cached_files.begin();
+    auto end = m_cached_files.end();
+    while (it != end)
+    {
+      if (game_paths.erase((*it)->GetFilePath()))
+      {
+        ++it;
+      }
+      else
+      {
+        cache_changed = true;
+        --end;
+        *it = std::move(*end);
+      }
+    }
+    m_cached_files.erase(it, m_cached_files.end());
+  }
+
+  // Now that the previous loop has run, game_paths only contains paths that
+  // aren't in m_cached_files, so we simply add all of them to m_cached_files.
+  for (const auto& path : game_paths)
+  {
+    auto file = std::make_shared<GameFile>(path);
+    if (file->IsValid())
+    {
+      cache_changed = true;
+      m_cached_files.push_back(std::move(file));
+    }
+  }
+
+  return cache_changed;
+}
+
+bool GameFileCache::UpdateAdditionalMetadata(const Core::TitleDatabase& title_database)
+{
+  bool cache_changed = false;
+
+  for (auto& file : m_cached_files)
+    cache_changed |= UpdateAdditionalMetadata(&file, title_database);
+
+  return cache_changed;
+}
+
+bool GameFileCache::UpdateAdditionalMetadata(std::shared_ptr<GameFile>* game_file,
+                                             const Core::TitleDatabase& title_database)
+{
+  const bool emu_state_changed = (*game_file)->EmuStateChanged();
+  const bool banner_changed = (*game_file)->BannerChanged();
+  const bool custom_title_changed = (*game_file)->CustomNameChanged(title_database);
+  if (!emu_state_changed && !banner_changed && !custom_title_changed)
+    return false;
+
+  // If a cached file needs an update, apply the updates to a copy and delete the original.
+  // This makes the usage of cached files in other threads safe.
+
+  std::shared_ptr<GameFile> copy = std::make_shared<GameFile>(**game_file);
+  if (emu_state_changed)
+    copy->EmuStateCommit();
+  if (banner_changed)
+    copy->BannerCommit();
+  if (custom_title_changed)
+    copy->CustomNameCommit();
+  *game_file = std::move(copy);
+
+  return true;
+}
+
+bool GameFileCache::Load()
+{
+  return SyncCacheFile(false);
+}
+
+bool GameFileCache::Save()
+{
+  return SyncCacheFile(true);
+}
+
+bool GameFileCache::SyncCacheFile(bool save)
+{
+  std::string filename(File::GetUserPath(D_CACHE_IDX) + "gamelist.cache");
+  const char* open_mode = save ? "wb" : "rb";
+  File::IOFile f(filename, open_mode);
+  if (!f)
+    return false;
+  bool success = false;
+  if (save)
+  {
+    // Measure the size of the buffer.
+    u8* ptr = nullptr;
+    PointerWrap p(&ptr, PointerWrap::MODE_MEASURE);
+    DoState(&p);
+    const size_t buffer_size = reinterpret_cast<size_t>(ptr);
+
+    // Then actually do the write.
+    std::vector<u8> buffer(buffer_size);
+    ptr = &buffer[0];
+    p.SetMode(PointerWrap::MODE_WRITE);
+    DoState(&p, buffer_size);
+    if (f.WriteBytes(buffer.data(), buffer.size()))
+      success = true;
+  }
+  else
+  {
+    std::vector<u8> buffer(f.GetSize());
+    if (buffer.size() && f.ReadBytes(buffer.data(), buffer.size()))
+    {
+      u8* ptr = buffer.data();
+      PointerWrap p(&ptr, PointerWrap::MODE_READ);
+      DoState(&p, buffer.size());
+      if (p.GetMode() == PointerWrap::MODE_READ)
+        success = true;
+    }
+  }
+  if (!success)
+  {
+    // If some file operation failed, try to delete the probably-corrupted cache
+    f.Close();
+    File::Delete(filename);
+  }
+  return success;
+}
+
+void GameFileCache::DoState(PointerWrap* p, u64 size)
+{
+  struct
+  {
+    u32 revision;
+    u64 expected_size;
+  } header = {CACHE_REVISION, size};
+  p->Do(header);
+  if (p->GetMode() == PointerWrap::MODE_READ)
+  {
+    if (header.revision != CACHE_REVISION || header.expected_size != size)
+    {
+      p->SetMode(PointerWrap::MODE_MEASURE);
+      return;
+    }
+  }
+  p->DoEachElement(m_cached_files, [](PointerWrap& state, std::shared_ptr<GameFile>& elem) {
+    if (state.GetMode() == PointerWrap::MODE_READ)
+      elem = std::make_shared<GameFile>();
+    elem->DoState(state);
+  });
+}
+
+}  // namespace DiscIO
diff --git a/Source/Core/UICommon/GameFileCache.h b/Source/Core/UICommon/GameFileCache.h
@@ -0,0 +1,58 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstddef>
+#include <functional>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+
+class PointerWrap;
+
+namespace Core
+{
+class TitleDatabase;
+}
+
+namespace UICommon
+{
+class GameFile;
+
+std::vector<std::string> FindAllGamePaths(const std::vector<std::string>& directories_to_scan,
+                                          bool recursive_scan);
+
+class GameFileCache
+{
+public:
+  void ForEach(std::function<void(const std::shared_ptr<const GameFile>&)> f) const;
+
+  void Clear();
+
+  std::shared_ptr<const GameFile> AddOrGet(const std::string& path, bool* cache_changed,
+                                           const Core::TitleDatabase& title_database);
+
+  // These functions return true if the call modified the cache.
+  bool Update(const std::vector<std::string>& all_game_paths);
+  bool UpdateAdditionalMetadata(const Core::TitleDatabase& title_database);
+
+  bool Load();
+  bool Save();
+
+private:
+  bool UpdateAdditionalMetadata(std::shared_ptr<GameFile>* game_file,
+                                const Core::TitleDatabase& title_database);
+
+  bool SyncCacheFile(bool save);
+  void DoState(PointerWrap* p, u64 size = 0);
+
+  std::vector<std::shared_ptr<GameFile>> m_cached_files;
+};
+
+}  // namespace UICommon
diff --git a/Source/Core/UICommon/UICommon.cpp b/Source/Core/UICommon/UICommon.cpp
@@ -2,16 +2,20 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <cmath>
 #include <memory>
 #ifdef _WIN32
 #include <shlobj.h>  // for SHGetFolderPath
 #endif
 
+#include "Common/Common.h"
 #include "Common/CommonPaths.h"
 #include "Common/Config/Config.h"
 #include "Common/FileUtil.h"
 #include "Common/Logging/LogManager.h"
+#include "Common/MathUtil.h"
 #include "Common/MsgHandler.h"
+#include "Common/StringUtil.h"
 
 #include "Core/ConfigLoaders/BaseConfigLoader.h"
 #include "Core/ConfigManager.h"
@@ -313,4 +317,21 @@ void EnableScreenSaver(bool enable)
 #endif
 }
 
+std::string FormatSize(u64 bytes)
+{
+  // i18n: The symbol for the unit "bytes"
+  const char* const unit_symbols[] = {_trans("B"),   _trans("KiB"), _trans("MiB"), _trans("GiB"),
+                                      _trans("TiB"), _trans("PiB"), _trans("EiB")};
+
+  // Find largest power of 2 less than size.
+  // div 10 to get largest named unit less than size
+  // 10 == log2(1024) (number of B in a KiB, KiB in a MiB, etc)
+  // Max value is 63 / 10 = 6
+  const int unit = IntLog2(std::max<u64>(bytes, 1)) / 10;
+
+  // Don't need exact values, only 5 most significant digits
+  const double unit_size = std::pow(2, unit * 10);
+  return StringFromFormat("%.2f %s", bytes / unit_size, GetStringT(unit_symbols[unit]).c_str());
+}
+
 }  // namespace UICommon
diff --git a/Source/Core/UICommon/UICommon.h b/Source/Core/UICommon/UICommon.h
@@ -25,4 +25,8 @@ void SetUserDirectory(const std::string& custom_path);
 bool TriggerSTMPowerEvent();
 
 void SaveWiimoteSources();
+
+// Return a pretty file size string from byte count.
+// e.g. 1134278 -> "1.08 MiB"
+std::string FormatSize(u64 bytes);
 }  // namespace UICommon
diff --git a/Source/Core/UICommon/UICommon.vcxproj b/Source/Core/UICommon/UICommon.vcxproj
@@ -51,12 +51,16 @@
       <DisableSpecificWarnings>4200;%(DisableSpecificWarnings)</DisableSpecificWarnings>
     </ClCompile>
     <ClCompile Include="VideoUtils.cpp" />
+    <ClCompile Include="GameFile.cpp" />
+    <ClCompile Include="GameFileCache.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="CommandLineParse.h" />
     <ClInclude Include="UICommon.h" />
     <ClInclude Include="Disassembler.h" />
     <ClInclude Include="USBUtils.h" />
+    <ClInclude Include="GameFile.h" />
+    <ClInclude Include="GameFileCache.h" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="$(ExternalsDir)cpp-optparse\cpp-optparse.vcxproj">