diff --git a/src/pystencils/jit/gpu_cupy.py b/src/pystencils/jit/gpu_cupy.py
index 54fb411738f4376a58ab49157259ecc6c8357de8..331b58ce51199a1a16af401e444958abc401985d 100644
--- a/src/pystencils/jit/gpu_cupy.py
+++ b/src/pystencils/jit/gpu_cupy.py
@@ -242,7 +242,7 @@ class CupyKernelWrapper(KernelWrapper):
 
 class CupyJit(JitBase):
 
-    def __init__(self, default_block_size: Sequence[int] = (128, 2, 1)):
+    def __init__(self, default_block_size: Sequence[int] = (128, 1, 1)):
         self._runtime_headers = {"<cstdint>"}
 
         if len(default_block_size) > 3: