diff --git a/.github/workflows/Ubuntu.yml b/.github/workflows/Ubuntu.yml
index 79f4d3322..b3edcf78b 100644
--- a/.github/workflows/Ubuntu.yml
+++ b/.github/workflows/Ubuntu.yml
@@ -46,11 +46,19 @@ jobs:
             cuda_arch: "50"
             hostcxx: clang-14 # 7-16
             os: ubuntu-22.04
-          # cuda 12.0 with oldest clang on ubuntu 22.04.
+          # cuda 12.0 with oldest clang on ubuntu 20.04.
           - cuda: "12.0"
             cuda_arch: "50"
-            hostcxx: clang-11 # 7-15
-            os: ubuntu-22.04
+            hostcxx: clang-9 # 7-15
+            os: ubuntu-20.04
+          - cuda: "12.0"
+            cuda_arch: "50"
+            hostcxx: clang-8 # 7-15
+            os: ubuntu-20.04
+          - cuda: "12.0"
+            cuda_arch: "50"
+            hostcxx: clang-7 # 7-15
+            os: ubuntu-20.04
         python: 
           - "3.12"
         config: