diff --git a/.circleci/config.yml b/.circleci/config.yml
index 37dcf7a98e..dd4b8dbb71 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,10 +3,10 @@ jobs:
   j8_jvm_upgrade_dtests:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 2
+    parallelism: 1
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -88,8 +88,8 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   build:
@@ -169,17 +169,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_dtests-no-vnodes:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 100
+    parallelism: 4
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -227,17 +227,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_upgradetests-no-vnodes:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 100
+    parallelism: 4
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -326,14 +326,14 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   utests_stress:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
     parallelism: 1
@@ -372,17 +372,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_unit_tests:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 100
+    parallelism: 4
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -464,17 +464,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_dtests-with-vnodes:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 100
+    parallelism: 4
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -522,17 +522,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_jvm_dtests:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 2
+    parallelism: 1
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -614,14 +614,14 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   utests_long:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
     parallelism: 1
@@ -660,17 +660,17 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   utests_compression:
     docker:
     - image: spod/cassandra-testing-ubuntu1810-java11-w-dependencies:20190306
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/
     shell: /bin/bash -eo pipefail -l
-    parallelism: 100
+    parallelism: 4
     steps:
     - attach_workspace:
         at: /home/cassandra
@@ -752,8 +752,8 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
   j8_dtest_jars_build:
@@ -827,8 +827,8 @@ jobs:
     - CASSANDRA_SKIP_SYNC: true
     - DTEST_REPO: git://github.com/apache/cassandra-dtest.git
     - DTEST_BRANCH: master
-    - CCM_MAX_HEAP_SIZE: 2048M
-    - CCM_HEAP_NEWSIZE: 512M
+    - CCM_MAX_HEAP_SIZE: 1024M
+    - CCM_HEAP_NEWSIZE: 256M
     - JAVA_HOME: /usr/lib/jvm/java-8-openjdk-amd64
     - JDK_HOME: /usr/lib/jvm/java-8-openjdk-amd64
 workflows: