diff --git a/soc/targets/artiq_pipistrello.py b/soc/targets/artiq_pipistrello.py
index be7ba6312..36d57f2e4 100644
--- a/soc/targets/artiq_pipistrello.py
+++ b/soc/targets/artiq_pipistrello.py
@@ -105,7 +105,7 @@ trce -v 12 -fastpaths -tsi {build_name}.tsi -o {build_name}.twr {build_name}.ncd
 
         phy = ttl_simple.Output(platform.request("ext_led", 0))
         self.submodules += phy
-        rtio_channels.append(rtio.Channel.from_phy(phy, ofifo_depth=256))
+        rtio_channels.append(rtio.Channel.from_phy(phy, ofifo_depth=4))
 
         self.add_constant("RTIO_TTL_COUNT", len(rtio_channels))