diff --git a/pyebsdindex/opencl/nlpar_cl.py b/pyebsdindex/opencl/nlpar_cl.py
index 6f3f2a4..63250dd 100644
--- a/pyebsdindex/opencl/nlpar_cl.py
+++ b/pyebsdindex/opencl/nlpar_cl.py
@@ -100,7 +100,7 @@ def calcsigma_cl(self,nn=1,saturation_protect=True,automask=True, normalize_d=Fa
     #print(gpuid)
     clparams.get_context(gpu_id=gpuid, kfile = 'clnlpar.cl')
     clparams.get_queue()
-    target_mem = clparams.queue.device.max_mem_alloc_size
+    target_mem = clparams.queue.device.max_mem_alloc_size//2
     ctx = clparams.ctx
     prg = clparams.prg
     queue = clparams.queue
diff --git a/pyebsdindex/opencl/nlpar_clray.py b/pyebsdindex/opencl/nlpar_clray.py
index df5aff6..695cb8c 100644
--- a/pyebsdindex/opencl/nlpar_clray.py
+++ b/pyebsdindex/opencl/nlpar_clray.py
@@ -123,7 +123,7 @@ def calcnlpar_cl(self,chunksize=0, searchradius=None, lam = None, dthresh = None
                                                rescale = rescale,
                                                gpuid = gpuid)
 
-    target_mem = clparams.gpu[gpuid].max_mem_alloc_size//2
+    target_mem = clparams.gpu[gpuid].max_mem_alloc_size//3
     max_mem = clparams.gpu[gpuid].global_mem_size*0.75
     if target_mem*ngpuwrker > max_mem:
       target_mem = max_mem/ngpuwrker