diff --git a/ChangeLog b/ChangeLog
index 1c96f06fb..30a90e708 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,8 +10,8 @@ Features
    Gill).
  + #1226 A new French translation has begun, and will continue to be a work in
    progress for a while (thanks to YBSA R).
- + #1227 A new 'verify_l10n' utility ensures the localizations are in sync (thanks to
-   Wim Schuermann).
+ + #1227 A new 'verify_l10n' utility ensures the localizations are in sync
+   (thanks to Wim Schuermann).
  + #1250 Support out-of-tree test runs (thanks to Jakub Wilk).
  + #1256 Supports default values for UDA fields (thanks to Thomas Sullivan).
  + #1297 The task₋sync(5) man pages is rewritten with examples.
@@ -50,6 +50,7 @@ Features
    FreeBSD (thanks to Pietro Cerutti).
  + Performance improvements:
    + Optimizes indexing into pending.data for direct task access.
+   + Improved I/O performance with better defaults for buffer sizes.
 
 Bugs
  + #1195 Random seed not random enough - removed all random number code (thanks
diff --git a/src/File.cpp b/src/File.cpp
index ca5146ca6..9ddb8aac7 100644
--- a/src/File.cpp
+++ b/src/File.cpp
@@ -196,12 +196,13 @@ bool File::waitForLock ()
 void File::read (std::string& contents)
 {
   contents = "";
+  contents.reserve (size ());
 
   std::ifstream in (_data.c_str ());
   if (in.good ())
   {
     std::string line;
-    line.reserve (1024);
+    line.reserve (512 * 1024);
     while (getline (in, line))
       contents += line + "\n";
 
@@ -219,7 +220,7 @@ void File::read (std::vector <std::string>& contents)
   if (in.good ())
   {
     std::string line;
-    line.reserve (1024);
+    line.reserve (512 * 1024);
     while (getline (in, line))
       contents.push_back (line);