diff --git a/lib/mutant.rb b/lib/mutant.rb
index 095dc319..267dfc1b 100644
--- a/lib/mutant.rb
+++ b/lib/mutant.rb
@@ -28,6 +28,16 @@ module Mutant
 
   SCOPE_OPERATOR = '::'.freeze
 
+  # Test if CI is detected via environment
+  #
+  # @return [Boolean]
+  #
+  # @api private
+  #
+  def self.ci?
+    ENV.key?('CI')
+  end
+
   # Lookup constant for location
   #
   # @param [String] location
@@ -199,6 +209,8 @@ require 'mutant/zombifier/file'
 module Mutant
   # Reopen class to initialize constant to avoid dep circle
   class Config
+    CI_DEFAULT_PROCESSOR_COUNT = 2
+
     DEFAULT = new(
       debug:             false,
       fail_fast:         false,
@@ -209,7 +221,7 @@ module Mutant
       isolation:         Mutant::Isolation::Fork,
       reporter:          Reporter::CLI.build($stdout),
       zombie:            false,
-      processes:         Parallel.processor_count,
+      processes:         Mutant.ci? ? CI_DEFAULT_PROCESSOR_COUNT : Parallel.processor_count,
       expected_coverage: 100.0
     )
   end # Config
diff --git a/lib/mutant/reporter/cli.rb b/lib/mutant/reporter/cli.rb
index 14ec28f7..ac4961be 100644
--- a/lib/mutant/reporter/cli.rb
+++ b/lib/mutant/reporter/cli.rb
@@ -13,10 +13,9 @@ module Mutant
       # @api private
       #
       def self.build(output)
-        ci = ENV.key?('CI')
         tty = output.respond_to?(:tty?) && output.tty?
         format =
-          if !ci && tty && Tput::INSTANCE.available
+          if !Mutant.ci? && tty && Tput::INSTANCE.available
             Format::Framed.new(tty:  tty, tput: Tput::INSTANCE)
           else
             Format::Progressive.new(tty: tty)
diff --git a/spec/unit/mutant_spec.rb b/spec/unit/mutant_spec.rb
index 0abd0ca2..60066fd3 100644
--- a/spec/unit/mutant_spec.rb
+++ b/spec/unit/mutant_spec.rb
@@ -1,6 +1,18 @@
 RSpec.describe Mutant do
   let(:object) { described_class }
 
+  describe '.ci?' do
+    subject { object.ci? }
+
+    let(:result) { double('Result') }
+
+    before do
+      expect(ENV).to receive(:key?).with('CI').and_return(result)
+    end
+
+    it { should be(result) }
+  end
+
   describe '.zombify' do
     subject { object.zombify }