diff --git a/src/stcal/ramp_fitting/ols_fit.py b/src/stcal/ramp_fitting/ols_fit.py
index 5baf8c216..0b5bda7ab 100644
--- a/src/stcal/ramp_fitting/ols_fit.py
+++ b/src/stcal/ramp_fitting/ols_fit.py
@@ -658,8 +658,8 @@ def ols_ramp_fit_single(ramp_data, buffsize, save_opt, readnoise_2d, gain_2d, we
         The tuple of computed optional results arrays for fitting.
     """
 
-    use_c = False
-    # use_c = True
+    # use_c = False
+    use_c = True
     if use_c:
         print(" ")
         print("=" * 80)