diff --git a/src/crystal/system/win32/time.cr b/src/crystal/system/win32/time.cr
index cef017fe9e06..55c6d147f39d 100644
--- a/src/crystal/system/win32/time.cr
+++ b/src/crystal/system/win32/time.cr
@@ -20,6 +20,8 @@ module Crystal::System::Time
   end
 
   def self.compute_utc_seconds_and_nanoseconds : {Int64, Int32}
+    # TODO: Needs a check if `GetSystemTimePreciseAsFileTime` is actually available (only >= Windows 8)
+    # and use `GetSystemTimeAsFileTime` as fallback.
     LibC.GetSystemTimePreciseAsFileTime(out filetime)
     since_epoch = (filetime.dwHighDateTime.to_u64 << 32) | filetime.dwLowDateTime.to_u64