diff --git a/doc/api/crypto.md b/doc/api/crypto.md
index f2c288d2f797f9..0a6b92afdbfd56 100644
--- a/doc/api/crypto.md
+++ b/doc/api/crypto.md
@@ -1826,6 +1826,11 @@ Note that this API uses libuv's threadpool, which can have surprising and
 negative performance implications for some applications, see the
 [`UV_THREADPOOL_SIZE`][] documentation for more information.
 
+*Note*: The asynchronous version of `crypto.randomBytes()` is carried out
+in a single threadpool request. To minimize threadpool task length variation,
+partition large `randomBytes` requests when doing so as part of fulfilling a
+client request.
+
 ### crypto.randomFillSync(buffer[, offset][, size])
 <!-- YAML
 added: v7.10.0
@@ -1933,6 +1938,11 @@ Note that this API uses libuv's threadpool, which can have surprising and
 negative performance implications for some applications, see the
 [`UV_THREADPOOL_SIZE`][] documentation for more information.
 
+*Note*: The asynchronous version of `crypto.randomFill()` is carried out
+in a single threadpool request. To minimize threadpool task length variation,
+partition large `randomFill` requests when doing so as part of fulfilling a
+client request.
+
 ### crypto.setEngine(engine[, flags])
 <!-- YAML
 added: v0.11.11