diff --git a/Source/Core/Common/MemArenaUnix.cpp b/Source/Core/Common/MemArenaUnix.cpp
@@ -0,0 +1,94 @@
+// Copyright 2008 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "Common/MemArena.h"
+
+#include <cerrno>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <set>
+#include <string>
+
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "Common/CommonFuncs.h"
+#include "Common/CommonTypes.h"
+#include "Common/Logging/Log.h"
+#include "Common/MsgHandler.h"
+#include "Common/StringUtil.h"
+
+namespace Common
+{
+MemArena::MemArena() = default;
+MemArena::~MemArena() = default;
+
+void MemArena::GrabSHMSegment(size_t size)
+{
+  const std::string file_name = "/dolphin-emu." + std::to_string(getpid());
+  fd = shm_open(file_name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
+  if (fd == -1)
+  {
+    ERROR_LOG_FMT(MEMMAP, "shm_open failed: {}", strerror(errno));
+    return;
+  }
+  shm_unlink(file_name.c_str());
+  if (ftruncate(fd, size) < 0)
+    ERROR_LOG_FMT(MEMMAP, "Failed to allocate low memory space");
+}
+
+void MemArena::ReleaseSHMSegment()
+{
+  close(fd);
+}
+
+void* MemArena::CreateView(s64 offset, size_t size)
+{
+  return MapInMemoryRegion(offset, size, nullptr);
+}
+
+void MemArena::ReleaseView(void* view, size_t size)
+{
+  UnmapFromMemoryRegion(view, size);
+}
+
+u8* MemArena::ReserveMemoryRegion(size_t memory_size)
+{
+  const int flags = MAP_ANON | MAP_PRIVATE;
+  void* base = mmap(nullptr, memory_size, PROT_NONE, flags, -1, 0);
+  if (base == MAP_FAILED)
+  {
+    PanicAlertFmt("Failed to map enough memory space: {}", LastStrerrorString());
+    return nullptr;
+  }
+  munmap(base, memory_size);
+  return static_cast<u8*>(base);
+}
+
+void MemArena::ReleaseMemoryRegion()
+{
+}
+
+void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
+{
+  void* retval = mmap(base, size, PROT_READ | PROT_WRITE,
+                      MAP_SHARED | ((base == nullptr) ? 0 : MAP_FIXED), fd, offset);
+
+  if (retval == MAP_FAILED)
+  {
+    NOTICE_LOG_FMT(MEMMAP, "mmap failed");
+    return nullptr;
+  }
+  else
+  {
+    return retval;
+  }
+}
+
+void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
+{
+  munmap(view, size);
+}
+}  // namespace Common
diff --git a/Source/Core/Common/MemArenaWin.cpp b/Source/Core/Common/MemArenaWin.cpp
@@ -0,0 +1,72 @@
+// Copyright 2008 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "Common/MemArena.h"
+
+#include <cstddef>
+#include <cstdlib>
+#include <set>
+#include <string>
+
+#include <windows.h>
+
+#include "Common/CommonFuncs.h"
+#include "Common/CommonTypes.h"
+#include "Common/Logging/Log.h"
+#include "Common/MsgHandler.h"
+#include "Common/StringUtil.h"
+
+namespace Common
+{
+MemArena::MemArena() = default;
+MemArena::~MemArena() = default;
+
+void MemArena::GrabSHMSegment(size_t size)
+{
+  const std::string name = "dolphin-emu." + std::to_string(GetCurrentProcessId());
+  hMemoryMapping = CreateFileMapping(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
+                                     static_cast<DWORD>(size), UTF8ToTStr(name).c_str());
+}
+
+void MemArena::ReleaseSHMSegment()
+{
+  CloseHandle(hMemoryMapping);
+  hMemoryMapping = 0;
+}
+
+void* MemArena::CreateView(s64 offset, size_t size)
+{
+  return MapInMemoryRegion(offset, size, nullptr);
+}
+
+void MemArena::ReleaseView(void* view, size_t size)
+{
+  UnmapFromMemoryRegion(view, size);
+}
+
+u8* MemArena::ReserveMemoryRegion(size_t memory_size)
+{
+  u8* base = static_cast<u8*>(VirtualAlloc(nullptr, memory_size, MEM_RESERVE, PAGE_READWRITE));
+  if (!base)
+  {
+    PanicAlertFmt("Failed to map enough memory space: {}", GetLastErrorString());
+    return nullptr;
+  }
+  VirtualFree(base, 0, MEM_RELEASE);
+  return base;
+}
+
+void MemArena::ReleaseMemoryRegion()
+{
+}
+
+void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
+{
+  return MapViewOfFileEx(hMemoryMapping, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size, base);
+}
+
+void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
+{
+  UnmapViewOfFile(view);
+}
+}  // namespace Common
diff --git a/Source/Core/Core/HW/Memmap.cpp b/Source/Core/Core/HW/Memmap.cpp
@@ -314,7 +314,12 @@ void Init()
 
 bool InitFastmemArena()
 {
-  physical_base = Common::MemArena::FindMemoryBase();
+#if _ARCH_32
+  const size_t memory_size = 0x31000000;
+#else
+  const size_t memory_size = 0x400000000;
+#endif
+  physical_base = g_arena.ReserveMemoryRegion(memory_size);
 
   if (!physical_base)
   {
@@ -328,7 +333,7 @@ bool InitFastmemArena()
       continue;
 
     u8* base = physical_base + region.physical_address;
-    u8* view = (u8*)g_arena.CreateView(region.shm_position, region.size, base);
+    u8* view = (u8*)g_arena.MapInMemoryRegion(region.shm_position, region.size, base);
 
     if (base != view)
     {
@@ -354,7 +359,7 @@ void UpdateLogicalMemory(const PowerPC::BatTable& dbat_table)
 
   for (auto& entry : logical_mapped_entries)
   {
-    g_arena.ReleaseView(entry.mapped_pointer, entry.mapped_size);
+    g_arena.UnmapFromMemoryRegion(entry.mapped_pointer, entry.mapped_size);
   }
   logical_mapped_entries.clear();
   for (u32 i = 0; i < dbat_table.size(); ++i)
@@ -381,7 +386,7 @@ void UpdateLogicalMemory(const PowerPC::BatTable& dbat_table)
           u8* base = logical_base + logical_address + intersection_start - translated_address;
           u32 mapped_size = intersection_end - intersection_start;
 
-          void* mapped_pointer = g_arena.CreateView(position, mapped_size, base);
+          void* mapped_pointer = g_arena.MapInMemoryRegion(position, mapped_size, base);
           if (!mapped_pointer)
           {
             PanicAlertFmt("Memory::UpdateLogicalMemory(): Failed to map memory region at 0x{:08X} "
@@ -439,15 +444,17 @@ void ShutdownFastmemArena()
       continue;
 
     u8* base = physical_base + region.physical_address;
-    g_arena.ReleaseView(base, region.size);
+    g_arena.UnmapFromMemoryRegion(base, region.size);
   }
 
   for (auto& entry : logical_mapped_entries)
   {
-    g_arena.ReleaseView(entry.mapped_pointer, entry.mapped_size);
+    g_arena.UnmapFromMemoryRegion(entry.mapped_pointer, entry.mapped_size);
   }
   logical_mapped_entries.clear();
 
+  g_arena.ReleaseMemoryRegion();
+
   physical_base = nullptr;
   logical_base = nullptr;
 

diff --git a/Source/Core/DolphinLib.props b/Source/Core/DolphinLib.props
@@ -726,7 +726,7 @@
     <ClCompile Include="Common\MathUtil.cpp" />
     <ClCompile Include="Common\Matrix.cpp" />
     <ClCompile Include="Common\MD5.cpp" />
-    <ClCompile Include="Common\MemArena.cpp" />
+    <ClCompile Include="Common\MemArenaWin.cpp" />
     <ClCompile Include="Common\MemoryUtil.cpp" />
     <ClCompile Include="Common\MsgHandler.cpp" />
     <ClCompile Include="Common\NandPaths.cpp" />