diff --git a/dap/algos/streakfind.py b/dap/algos/streakfind.py
index 658d6fc..a3630d1 100644
--- a/dap/algos/streakfind.py
+++ b/dap/algos/streakfind.py
@@ -103,11 +103,15 @@ def _calc_snr(results, data, pf_pixel_mask):
 
 def _scale_whitefield(data, mask, whitefield, std,
                       r0: float = 0.0, r1: float = 0.5,
-                      n_iter: int = 12, lm: float = 9.0, num_threads: int = 1
+                      n_iter: int = 12, lm: float = 9.0, num_threads: int = 16
                       ):
     mask = mask & (std > 0.0)
-    y = np.where(mask, data / std, 0.0)[mask]  # must be newaxis
-    W = np.where(mask, whitefield / std, 0.0)[mask]  # must be newaxis
+    #y = np.where(mask, data / std, 0.0)[mask]  # must be newaxis
+    y = np.divide(data, std, out=np.zeros_like(data), where=mask)[mask]  # must be newaxis
+    #W = np.where(mask, whitefield / std, 0.0)[mask]  # must be newaxis
+
+    W = np.divide(whitefield, std, out=np.zeros_like(data), where=mask)[mask]  # must be newaxis
+    #W = np.where(mask, whitefield / std, 0.0)[mask]  # must be newaxis
 
     scales = robust_lsq(W=W[np.newaxis, :], y=y[np.newaxis, :], axis=1, r0=r0, r1=r1, n_iter=n_iter, lm=lm,
                             num_threads=num_threads)