diff --git a/Performance.md b/Performance.md
index 3c22822..10c9188 100644
--- a/Performance.md
+++ b/Performance.md
@@ -18,6 +18,10 @@ Some other notes on memory footprint:
  * importing nevow and twisted.web (for the web interface) raises the static
    footprint by about 3MB (from 12.8MB to 15.7MB).
 
+ * importing pycryptopp (which began on 09-Nov-2007) raises the static footprint
+   (on a 32-bit machine) by about 6MB (from 19MB to 25MB). The 64-bit machine
+   footprint was raised by 17MB (from 122MB to 139MB).
+
 The
 [32-bit memory usage graph](http://allmydata.org/tahoe-figleaf-graph/hanford.allmydata.com-tahoe_memstats.html)
 shows our static memory footprint on a 32bit machine (starting a node but not doing