cmark

diff --git a/benchmarks.md b/benchmarks.md
@@ -31,3 +31,10 @@ with the benchmark input and the time to run it with no input.
 not penalized by startup time.) A median of ten runs is taken.  The
 process is reniced to a high priority so that the system doesn't
 interrupt runs.
+
+Note that these benchmarks were done on a 32-bit machine.  On a 64-bit
+machines, sundown is significantly faster than cmark (0.146s vs 0.237s
+on Intel i5/OSX with Clang, 0.130s vs 0.191s on a 64-bit Debian VPS
+with GCC).  I do not know why the performance difference shows up on
+the 64-bit architecture and not the 32-bit, but that is something that
+might be investigated.