diff --git a/lib/rogue_one/detector.rb b/lib/rogue_one/detector.rb
index f889de1..9d635dc 100644
--- a/lib/rogue_one/detector.rb
+++ b/lib/rogue_one/detector.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "yaml"
+require "parallel"
 
 module RogueOne
   class Detector
@@ -10,7 +11,7 @@ class Detector
 
     def initialize(target:)
       @target = target
-      @memo = Hash.new(0)
+      @memo = {}
     end
 
     def report
@@ -38,14 +39,14 @@ def landing_pages
     end
 
     def inspect
-      top_100_domains.each do |domain|
+      results = Parallel.map(top_100_domains) do |domain|
         normal_result = normal_resolver.dig(domain, "A")
         target_result = target_resolver.dig(domain, "A")
 
-        if normal_result != target_result
-          @memo[target_result] += 1 if target_result
-        end
-      end
+        target_result if target_result && normal_result != target_result
+      end.compact
+
+      @memo = results.group_by(&:itself).map { |k, v| [k, v.length] }.to_h
     end
 
     def top_100_domains
diff --git a/rogue_one.gemspec b/rogue_one.gemspec
index 68180cf..e800472 100644
--- a/rogue_one.gemspec
+++ b/rogue_one.gemspec
@@ -29,5 +29,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rake", "~> 12.3"
   spec.add_development_dependency "rspec", "~> 3.8"
 
+  spec.add_dependency "parallel", "~> 1.17"
   spec.add_dependency "thor", "~> 0.19"
 end
diff --git a/spec/rogue_one_spec.rb b/spec/rogue_one_spec.rb
index e74f1f4..dc811bc 100644
--- a/spec/rogue_one_spec.rb
+++ b/spec/rogue_one_spec.rb
@@ -6,6 +6,7 @@
   describe "#report" do
     before do
       allow(subject).to receive(:top_100_domains).and_return(%w(google.com))
+      allow(Parallel).to receive(:processor_count).and_return(0)
     end
 
     let(:report) { subject.report }