diff --git a/railties/CHANGELOG b/railties/CHANGELOG
index 864c618d63..5a80e21446 100644
--- a/railties/CHANGELOG
+++ b/railties/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Don't require rails/gem_builder during rails initialization, it's only needed for the gems:build task. [rick]
+
 * script/performance/profiler compatibility with the ruby-prof >= 0.5.0. Closes #9176. [Catfish]
 
 * Flesh out rake gems:unpack to unpack all gems, and add rake gems:build for native extensions. #11513 [ddollar]
diff --git a/railties/lib/initializer.rb b/railties/lib/initializer.rb
index 61fcddc5f0..8a5ca6f91b 100644
--- a/railties/lib/initializer.rb
+++ b/railties/lib/initializer.rb
@@ -7,7 +7,6 @@ require 'railties_path'
 require 'rails/version'
 require 'rails/plugin/locator'
 require 'rails/plugin/loader'
-require 'rails/gem_builder'
 require 'rails/gem_dependency'
 
 
diff --git a/railties/lib/rails/gem_builder.rb b/railties/lib/rails/gem_builder.rb
index 629726a5c6..e7e06d0008 100644
--- a/railties/lib/rails/gem_builder.rb
+++ b/railties/lib/rails/gem_builder.rb
@@ -1,3 +1,4 @@
+require 'rubygems'
 require 'rubygems/installer'
 
 module Rails
diff --git a/railties/lib/rails/gem_dependency.rb b/railties/lib/rails/gem_dependency.rb
index 8d6a748e4c..0b2e6eb93d 100644
--- a/railties/lib/rails/gem_dependency.rb
+++ b/railties/lib/rails/gem_dependency.rb
@@ -14,8 +14,7 @@ module Rails
       end
       @lib      = options[:lib]
       @source   = options[:source]
-      @loaded   = false
-      @load_paths_added = false
+      @loaded   = @frozen = @load_paths_added = false
       @unpack_directory = nil
     end
 
@@ -28,6 +27,7 @@ module Rails
         gem *args
       else
         $LOAD_PATH << File.join(unpacked_paths.first, 'lib')
+        @frozen = true
       end
       @load_paths_added = true
     rescue Gem::LoadError
@@ -47,6 +47,10 @@ module Rails
       $!.backtrace.each { |b| puts b }
     end
 
+    def frozen?
+      @frozen
+    end
+
     def loaded?
       @loaded
     end
diff --git a/railties/lib/tasks/gems.rake b/railties/lib/tasks/gems.rake
index 8f3fc51635..c8d5167be6 100644
--- a/railties/lib/tasks/gems.rake
+++ b/railties/lib/tasks/gems.rake
@@ -1,13 +1,18 @@
 desc "List the gems that this rails application depends on"
 task :gems => :environment do
   Rails.configuration.gems.each do |gem|
-    puts "[#{gem.loaded? ? '*' : ' '}] #{gem.name} #{gem.requirement.to_s}"
+    code = gem.loaded? ? (gem.frozen? ? "F" : "I") : " "
+    puts "[#{code}] #{gem.name} #{gem.requirement.to_s}"
   end
+  puts
+  puts "I = Installed"
+  puts "F = Frozen"
 end
 
 namespace :gems do
   desc "Build any native extensions for unpacked gems"
   task :build do
+    require 'rails/gem_builder'
     Dir[File.join(RAILS_ROOT, 'vendor', 'gems', '*')].each do |gem_dir|
       spec_file = File.join(gem_dir, '.specification')
       next unless File.exists?(spec_file)
@@ -26,12 +31,11 @@ namespace :gems do
   end
 
   desc "Unpacks the specified gem into vendor/gems."
-  task :unpack do
-    Rake::Task["environment"].invoke
+  task :unpack => :environment do
     require 'rubygems'
     require 'rubygems/gem_runner'
     Rails.configuration.gems.each do |gem|
-      next unless ENV['GEM'].blank? || ENV['GEM'] == gem.name
+      next unless !gem.frozen? && (ENV['GEM'].blank? || ENV['GEM'] == gem.name)
       gem.unpack_to(File.join(RAILS_ROOT, 'vendor', 'gems')) if gem.loaded?
     end
   end