diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..53c0059
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+0.1.5
+-----
+
+- Use [posix-spawn](https://github.com/rtomayko/posix-spawn) to instead of Kernel#exec to get better performance.
+  > fork(2) calls slow down as the parent process uses more memory due to the need to copy page tables.
diff --git a/letter_avatar.gemspec b/letter_avatar.gemspec
index 19aba99..bf6b83e 100644
--- a/letter_avatar.gemspec
+++ b/letter_avatar.gemspec
@@ -20,6 +20,8 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
+  spec.add_dependency 'posix-spawn', '>= 0.3.0'
+
   spec.add_development_dependency "bundler", "~> 1.3"
   spec.add_development_dependency "rake"
 end
diff --git a/lib/letter_avatar/avatar.rb b/lib/letter_avatar/avatar.rb
index d82f018..6558cc2 100644
--- a/lib/letter_avatar/avatar.rb
+++ b/lib/letter_avatar/avatar.rb
@@ -12,6 +12,8 @@ module LetterAvatar
 
     FILL_COLOR = 'rgba(255, 255, 255, 0.65)'.freeze
 
+    FONT_FILENAME = File.join(File.expand_path("../../", File.dirname(__FILE__)), "Roboto-Medium")
+
     class << self
 
       class Identity
@@ -64,21 +66,30 @@ module LetterAvatar
         color = identity.color
         letter = identity.letter
 
+
         filename = fullsize_path(identity)
 
-        instructions = %W{
+        commands = %W(
+          convert
           -size 240x240
           xc:#{to_rgb(color)}
           -pointsize 140
-          -font Roboto-Medium
+          -font #{FONT_FILENAME}
           -weight 500
           -fill '#{FILL_COLOR}'
           -gravity Center
           -annotate -0+10 '#{letter}'
           '#{filename}'
-        }
+        )
 
-        `convert #{instructions.join(" ")}`
+        command = commands.join(' ')
+
+        pid, stdin, stdout, stderr = POSIX::Spawn.popen4(command)
+        Process.waitpid(pid)
+        err = stderr.read
+        if err != nil && err.length > 0
+          raise "letter_avatar error: #{err.strip}"
+        end
 
         filename
       end
diff --git a/lib/letter_avatar/version.rb b/lib/letter_avatar/version.rb
index c073277..f5cc922 100644
--- a/lib/letter_avatar/version.rb
+++ b/lib/letter_avatar/version.rb
@@ -1,3 +1,3 @@
 module LetterAvatar
-  VERSION = "0.1.4"
+  VERSION = "0.1.5"
 end
--
libgit2 0.21.0