diff --git a/.github/scripts/check_diff.py b/.github/scripts/check_diff.py
index ee085f8cd9b..a18990235a4 100644
--- a/.github/scripts/check_diff.py
+++ b/.github/scripts/check_diff.py
@@ -127,7 +127,21 @@ def _get_configs_for_single_dir(job: str, dir_: str) -> List[Dict[str, str]]:
         return _get_pydantic_test_configs(dir_)
 
     if job == "codspeed":
-        py_versions = ["3.13"]
+        # CPU simulation (<1% variance, Valgrind-based) is the default.
+        # Partners with heavy SDK inits use walltime instead to keep CI fast.
+        CODSPEED_WALLTIME_DIRS = {
+            "libs/core",
+            "libs/partners/fireworks",  # ~328s under simulation
+            "libs/partners/openai",  # 6 benchmarks, ~6 min under simulation
+        }
+        mode = "walltime" if dir_ in CODSPEED_WALLTIME_DIRS else "simulation"
+        return [
+            {
+                "working-directory": dir_,
+                "python-version": "3.13",
+                "codspeed-mode": mode,
+            }
+        ]
     elif dir_ == "libs/core":
         py_versions = ["3.10", "3.11", "3.12", "3.13", "3.14"]
     # custom logic for specific directories
diff --git a/.github/workflows/check_diffs.yml b/.github/workflows/check_diffs.yml
index 1d483349378..a86246f8378 100644
--- a/.github/workflows/check_diffs.yml
+++ b/.github/workflows/check_diffs.yml
@@ -236,7 +236,7 @@ jobs:
             else
               uv run --no-sync pytest ./tests/unit_tests/ -m benchmark --codspeed
             fi
-          mode: ${{ matrix.job-configs.working-directory == 'libs/core' && 'walltime' || 'simulation' }}
+          mode: ${{ matrix.job-configs.codspeed-mode }}
 
   # Final status check - ensures all required jobs passed before allowing merge
   ci_success: