diff --git a/lib/transfer.c b/lib/transfer.c
index 69df214ce4..27843f50cc 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -980,7 +980,15 @@ static CURLcode readwrite_upload(struct Curl_easy *data,
     if(result)
       return result;
 
-    win_update_buffer_size(conn->writesockfd);
+#if defined(WIN32) && defined(USE_WINSOCK)
+    {
+      struct curltime n = Curl_now();
+      if(Curl_timediff(n, k->last_sndbuf_update) > 1000) {
+        win_update_buffer_size(conn->writesockfd);
+        k->last_sndbuf_update = n;
+      }
+    }
+#endif
 
     if(k->pendingheader) {
       /* parts of what was sent was header */
diff --git a/lib/urldata.h b/lib/urldata.h
index ca8e3074d7..d7d104d419 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -686,6 +686,10 @@ struct SingleRequest {
   } p;
 #ifndef CURL_DISABLE_DOH
   struct dohdata *doh; /* DoH specific data for this request */
+#endif
+#if defined(WIN32) && defined(USE_WINSOCK)
+  struct curltime last_sndbuf_update;  /* last time readwrite_upload called
+                                          win_update_buffer_size */
 #endif
   unsigned char setcookies;
   unsigned char writer_stack_depth; /* Unencoding stack depth. */