diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 2e86633a09..7156b2a0af 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1291,7 +1291,7 @@ pref("javascript.options.mem.high_water_mark", 128);
 pref("javascript.options.mem.max", -1);
 pref("javascript.options.mem.gc_per_zone", true);
 pref("javascript.options.mem.gc_incremental", true);
-pref("javascript.options.mem.gc_incremental_slice_ms", 10);
+pref("javascript.options.mem.gc_incremental_slice_ms", 20);
 pref("javascript.options.mem.gc_generational", true);
 pref("javascript.options.mem.gc_compacting", true);
 pref("javascript.options.mem.log", false);