diff --git a/src/os.c b/src/os.c
index 9edcd06..5d87203 100644
--- a/src/os.c
+++ b/src/os.c
@@ -220,7 +220,18 @@ static void* mi_win_virtual_allocx(void* addr, size_t size, size_t try_alignment
       _mi_warning_message("unable to allocate huge (1GiB) page, trying large (2MiB) page instead (error %lx)\n", err);
     }
   }
-  
+#endif
+#if (MI_INTPTR_SIZE >= 8) 
+  // on 64-bit systems, use the virtual address area after 4TiB for 4MiB aligned allocations
+  static volatile intptr_t aligned_base = ((intptr_t)4 << 40); // starting at 4TiB
+  if (addr == NULL && try_alignment > 0 && try_alignment <= MI_SEGMENT_SIZE && (size%MI_SEGMENT_SIZE) == 0) {
+	  intptr_t hint = mi_atomic_add(&aligned_base, size) - size;
+	  if (hint%try_alignment == 0) {
+		  return VirtualAlloc((void*)hint, size, flags, PAGE_READWRITE);      
+	  }
+  }
+#endif
+#if defined(MEM_EXTENDED_PARAMETER_TYPE_BITS)  
   // on modern Windows try use VirtualAlloc2 for aligned allocation
   if (try_alignment > 0 && (try_alignment % _mi_os_page_size()) == 0 && pVirtualAlloc2 != NULL) {
     MEM_ADDRESS_REQUIREMENTS reqs = { 0 };
@@ -781,7 +792,7 @@ int mi_reserve_huge_os_pages( size_t pages, double max_secs ) mi_attr_noexcept
   // Allocate one page at the time but try to place them contiguously
   // We allocate one page at the time to be able to abort if it takes too long
   double start_t = _mi_clock_start();
-  uint8_t* start = (uint8_t*)((uintptr_t)8 << 40); // 8TiB virtual start address
+  uint8_t* start = (uint8_t*)((uintptr_t)16 << 40); // 16TiB virtual start address
   uint8_t* addr = start;  // current top of the allocations
   for (size_t page = 0; page < pages; page++, addr += MI_HUGE_OS_PAGE_SIZE ) {
     // allocate lorgu pages