diff --git a/hysop/codegen/kernels/tests/test_directional_stretching.py b/hysop/codegen/kernels/tests/test_directional_stretching.py
index b7802ecea756ca9a822b9104f661fa7e04f1fa72..3b0c038787072f70133c416bd71bf2108616d04d 100644
--- a/hysop/codegen/kernels/tests/test_directional_stretching.py
+++ b/hysop/codegen/kernels/tests/test_directional_stretching.py
@@ -17,7 +17,7 @@ class TestDirectionalStretching(object):
         queue = cl.CommandQueue(typegen.context)
         ctx = typegen.context
 
-        grid_size = np.asarray([256,256,256])
+        grid_size = np.asarray([2048,10,10])
         compute_grid_ghosts = np.asarray([3*4,0,0])
         compute_grid_size   = grid_size + 2*compute_grid_ghosts
 
@@ -108,8 +108,8 @@ class TestDirectionalStretching(object):
         cls.host_buffers_gpu       = host_buffers_gpu
         cls.device_buffers         = device_buffers
 
-        cls.local_work_size = np.asarray([30,1,1])
-        cls.work_load       = np.asarray([1,4,4])
+        cls.local_work_size = np.asarray([1024,1,1])
+        cls.work_load       = np.asarray([1,1,1])
         cls.inv_dx = inv_dx
         cls.dt = dtype(0.5)
 
@@ -400,7 +400,7 @@ class TestDirectionalStretching(object):
         for (name,host,dev) in buffers:
             (l1,l2,linf) = self._distances(host,dev,view)
             print '\t{} -> l1={}  l2={}  linf={}'.format(name,l1,l2,linf)
-            if l2>1e-11:
+            if l2>1e-8:
                 err_buffers.append(name)
                 good = False
         if not good: