diff --git a/src/Composer/Command/InstallCommand.php b/src/Composer/Command/InstallCommand.php
index d3f450c50..038406a34 100644
--- a/src/Composer/Command/InstallCommand.php
+++ b/src/Composer/Command/InstallCommand.php
@@ -15,6 +15,7 @@ namespace Composer\Command;
 use Composer\Installer;
 use Composer\Plugin\CommandEvent;
 use Composer\Plugin\PluginEvents;
+use Composer\Util\HttpDownloader;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Input\InputArgument;
@@ -93,6 +94,10 @@ EOT
 
         $composer = $this->getComposer(true, $input->getOption('no-plugins'));
 
+        if ((!$composer->getLocker() || !$composer->getLocker()->isLocked()) && !HttpDownloader::isCurlEnabled()) {
+            $io->writeError('<warning>Composer is operating significantly slower than normal because you do not have the PHP curl extension enabled.</warning>');
+        }
+
         $commandEvent = new CommandEvent(PluginEvents::COMMAND, 'install', $input, $output);
         $composer->getEventDispatcher()->dispatch($commandEvent->getName(), $commandEvent);
 
diff --git a/src/Composer/Command/UpdateCommand.php b/src/Composer/Command/UpdateCommand.php
index 60a4758f1..84d329ba5 100644
--- a/src/Composer/Command/UpdateCommand.php
+++ b/src/Composer/Command/UpdateCommand.php
@@ -19,6 +19,7 @@ use Composer\IO\IOInterface;
 use Composer\Plugin\CommandEvent;
 use Composer\Plugin\PluginEvents;
 use Composer\Package\Version\VersionParser;
+use Composer\Util\HttpDownloader;
 use Composer\Semver\Constraint\MultiConstraint;
 use Composer\Package\Link;
 use Symfony\Component\Console\Helper\Table;
@@ -114,6 +115,10 @@ EOT
 
         $composer = $this->getComposer(true, $input->getOption('no-plugins'));
 
+        if (!HttpDownloader::isCurlEnabled()) {
+            $io->writeError('<warning>Composer is operating significantly slower than normal because you do not have the PHP curl extension enabled.</warning>');
+        }
+
         $packages = $input->getArgument('packages');
         $reqs = $this->formatRequirements($input->getOption('with'));
 
diff --git a/src/Composer/Console/Application.php b/src/Composer/Console/Application.php
index cd78684c1..76629d9c4 100644
--- a/src/Composer/Console/Application.php
+++ b/src/Composer/Console/Application.php
@@ -237,11 +237,11 @@ class Application extends BaseApplication
             }
 
             if (extension_loaded('xdebug') && !getenv('COMPOSER_DISABLE_XDEBUG_WARN')) {
-                $io->writeError('<warning>You are running composer with Xdebug enabled. This has a major impact on runtime performance. See https://getcomposer.org/xdebug</warning>');
+                $io->writeError('<warning>Composer is operating slower than normal because you have Xdebug enabled. See https://getcomposer.org/xdebug</warning>');
             }
 
             if (defined('COMPOSER_DEV_WARNING_TIME') && $commandName !== 'self-update' && $commandName !== 'selfupdate' && time() > COMPOSER_DEV_WARNING_TIME) {
-                $io->writeError(sprintf('<warning>Warning: This development build of composer is over 60 days old. It is recommended to update it by running "%s self-update" to get the latest version.</warning>', $_SERVER['PHP_SELF']));
+                $io->writeError(sprintf('<warning>Warning: This development build of Composer is over 60 days old. It is recommended to update it by running "%s self-update" to get the latest version.</warning>', $_SERVER['PHP_SELF']));
             }
 
             if (