diff --git a/tests/functional_tests/test_cases/gpt/gpt3_345m_nightly_dgx_a100_1N8G_mcore_tp2_pp2_ep2_te_4experts2parallel/model_config.yaml b/tests/functional_tests/test_cases/gpt/gpt3_345m_nightly_dgx_a100_1N8G_mcore_tp2_pp2_ep2_te_4experts2parallel/model_config.yaml
index d50c59d5f6..150d96aaee 100644
--- a/tests/functional_tests/test_cases/gpt/gpt3_345m_nightly_dgx_a100_1N8G_mcore_tp2_pp2_ep2_te_4experts2parallel/model_config.yaml
+++ b/tests/functional_tests/test_cases/gpt/gpt3_345m_nightly_dgx_a100_1N8G_mcore_tp2_pp2_ep2_te_4experts2parallel/model_config.yaml
@@ -50,4 +50,5 @@ MODEL_ARGS:
   --ckpt-format: torch_dist
   --data-cache-path: ${DATA_CACHE_PATH}
   --bf16: true
+  --attention-backend: unfused
 TEST_TYPE: regular
diff --git a/tests/functional_tests/test_cases/gpt/gpt3_nightly_mcore_te_tp2_pp1_modelopt_distill_resume/model_config.yaml b/tests/functional_tests/test_cases/gpt/gpt3_nightly_mcore_te_tp2_pp1_modelopt_distill_resume/model_config.yaml
index a32a8f28b9..fc75e1cbbb 100644
--- a/tests/functional_tests/test_cases/gpt/gpt3_nightly_mcore_te_tp2_pp1_modelopt_distill_resume/model_config.yaml
+++ b/tests/functional_tests/test_cases/gpt/gpt3_nightly_mcore_te_tp2_pp1_modelopt_distill_resume/model_config.yaml
@@ -62,4 +62,5 @@ MODEL_ARGS:
   --ckpt-format: torch_dist
   --data-cache-path: ${DATA_CACHE_PATH}
   --bf16: true
+  --attention-backend: unfused
 TEST_TYPE: ckpt-resume
diff --git a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp1_pp1_vp1_resume_torch/model_config.yaml b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp1_pp1_vp1_resume_torch/model_config.yaml
index 798f00c902..bde4e7200b 100644
--- a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp1_pp1_vp1_resume_torch/model_config.yaml
+++ b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp1_pp1_vp1_resume_torch/model_config.yaml
@@ -51,4 +51,5 @@ MODEL_ARGS:
   --deterministic-mode: true
   --attention-softmax-in-fp32: true
   --ckpt-format: torch
+  --attention-backend: unfused
 TEST_TYPE: ckpt-resume
diff --git a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1/model_config.yaml b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1/model_config.yaml
index df56656bd6..289e213759 100644
--- a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1/model_config.yaml
+++ b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1/model_config.yaml
@@ -51,4 +51,5 @@ MODEL_ARGS:
   --deterministic-mode: true
   --attention-softmax-in-fp32: true
   --ckpt-format: torch
+  --attention-backend: unfused
 TEST_TYPE: regular
diff --git a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1_sequence_parallel/model_config.yaml b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1_sequence_parallel/model_config.yaml
index 940b85cfab..8cfc7e4253 100644
--- a/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1_sequence_parallel/model_config.yaml
+++ b/tests/functional_tests/test_cases/t5/t5_220m_nightly_dgx_a100_1N8G_mcore_te_tp2_pp1_vp1_sequence_parallel/model_config.yaml
@@ -52,4 +52,5 @@ MODEL_ARGS:
   --deterministic-mode: true
   --attention-softmax-in-fp32: true
   --ckpt-format: torch
+  --attention-backend: unfused
 TEST_TYPE: regular