diff --git a/Performance.md b/Performance.md
index 1477591..3c22822 100644
--- a/Performance.md
+++ b/Performance.md
@@ -40,7 +40,9 @@ of reasons for it to be 2x, but the results show something closer to 6x.
 Using a 3-server testnet in colo and an uploading node at home (on a DSL line
 that gets about 78kBps upstream and has a 14ms ping time to colo) using
 0.5.1-34 takes 820ms-900ms per 1kB file uploaded (80-90s for 100 files, 819s
-for 1000 files).
+for 1000 files). The DSL speed results are occasionally worse than usual,
+when the owner of the DSL line is using it for other purposes while a test is
+taking place.
 
 'scp' of 3.3kB files (simulating expansion) takes 8.3s for 100 files and 79s
 for 1000 files, 80ms each.