diff --git a/hysop/__init__.py b/hysop/__init__.py
index 750619a55373226f3c871a06a5b96af9e74a0099..6a967dca544734e145ba406a95ea0336b0cc1c81 100644
--- a/hysop/__init__.py
+++ b/hysop/__init__.py
@@ -44,7 +44,7 @@ __TEST_ALL_OPENCL_PLATFORMS__ = get_env('TEST_ALL_OPENCL_PLATFORMS', False)
 __ENABLE_LONG_TESTS__ = get_env('ENABLE_LONG_TESTS', False)
 
 # OpenCL
-__DEFAULT_PLATFORM_ID__ = 0
+__DEFAULT_PLATFORM_ID__ = 1
 __DEFAULT_DEVICE_ID__   = 0
 
 if __MPI_ENABLED__:
diff --git a/hysop/backend/device/opencl/operator/custom_symbolic.py b/hysop/backend/device/opencl/operator/custom_symbolic.py
index f9fcd273025477d968eac0ece694f71b15a8a26e..7eac15b1536092916ddc93decdc71c09bec0d072 100644
--- a/hysop/backend/device/opencl/operator/custom_symbolic.py
+++ b/hysop/backend/device/opencl/operator/custom_symbolic.py
@@ -62,7 +62,6 @@ class OpenClCustomSymbolicOperator(CustomSymbolicOperatorBase, OpenClOperator):
         evt = self.kl(queue=queue, **self._update_input_params())
         for sout in self.output_discrete_fields.values():
             evt = sout.exchange_ghosts(queue=queue, evt=evt)
-        evt.wait()
     
     @classmethod
     def supports_mpi(cls):
diff --git a/hysop/backend/device/opencl/operator/derivative.py b/hysop/backend/device/opencl/operator/derivative.py
index a59a3fbb6f1806d556d08ac411e33d6b969f5079..ef81f422b9c68ba3a7048bbbf2c1f5a9358eddb1 100644
--- a/hysop/backend/device/opencl/operator/derivative.py
+++ b/hysop/backend/device/opencl/operator/derivative.py
@@ -48,5 +48,3 @@ class OpenClSpaceDerivative(SpaceDerivativeBase, OpenClSymbolic):
         queue = self.cl_env.default_queue
         evt = self.kernel(queue=queue, **self.update_parameters())
         evt = self.dFout.exchange_ghosts(queue=queue, evt=evt)
-        evt.wait()
-    
diff --git a/hysop/backend/device/opencl/operator/transpose.py b/hysop/backend/device/opencl/operator/transpose.py
index d93a66501b8940d861c05043fdfa367dc8dc00b4..44212648376e79b3521a2e669478975a1f826400 100644
--- a/hysop/backend/device/opencl/operator/transpose.py
+++ b/hysop/backend/device/opencl/operator/transpose.py
@@ -71,7 +71,6 @@ class OpenClTranspose(TransposeOperatorBase, OpenClOperator):
         
         kernel_launcher = self._kernel_launcher
         evt = kernel_launcher(queue=queue)
-        evt.wait()
 
     @classmethod
     def supports_mpi(cls):