diff --git a/spec/active_record/slave/model_spec.rb b/spec/active_record/slave/model_spec.rb
index 10db424..86a2082 100644
--- a/spec/active_record/slave/model_spec.rb
+++ b/spec/active_record/slave/model_spec.rb
@@ -27,7 +27,7 @@
 
   describe "multi thread" do
     before do
-      Parallel.each((0..99).to_a, :in_threads => 8) do |dummy|
+      Parallel.each((0..99).to_a, :in_threads => 2) do |dummy|
         User.connection_pool.with_connection do
           User.create name: "test#{dummy}"
         end
@@ -35,7 +35,7 @@
     end
 
     it "returns writed models" do
-      Parallel.each((0..14).to_a, :in_threads => 8) do |dummy|
+      Parallel.each((0..14).to_a, :in_threads => 2) do |dummy|
         User.slave_for.connection_pool.with_connection do
           expect(User.slave_for.all.count).to eq 100
         end