diff --git a/mdbx.h b/mdbx.h
index 771402ee..ffb8ef69 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -2190,7 +2190,8 @@ typedef enum MDBX_option {
    * spill to disk instead.
    *
    * The `MDBX_opt_txn_dp_limit` controls described threshold for the current
-   * process. Default is 65536, it is usually enough for most cases. */
+   * process. Default is 1/42 of the sum of whole and currently available RAM
+   * size, which the same ones are reported by \ref mdbx_get_sysraminfo(). */
   MDBX_opt_txn_dp_limit,
 
   /** \brief Controls the in-process initial allocation size for dirty pages