diff --git a/test/bench-vector.test.js b/test/bench-vector.test.js
index b6e982b..365c160 100644
--- a/test/bench-vector.test.js
+++ b/test/bench-vector.test.js
@@ -179,7 +179,7 @@ tape('vector bench async', function(assert) {
                 console.log("Skipping rate assertion, since we are running in debug mode");
             } else {
                 assert.equal(rate_async > 50, true, 'render ' + total + ' tiles @ ' + rate_async.toFixed(1) + ' tiles/sec');
-                assert.equal(rate_async + 20 > rate_deferred, true); // should be at least roughly the same speed or faster
+                assert.equal(rate_async + 20 > rate_deferred, true, (rate_async+20).toFixed(1) + ' (async) > ' + rate_deferred.toFixed(1) + ' (deferred) tiles/sec'); // should be at least roughly the same speed or faster
             }
 
             assert.equal(total, 341);