diff --git a/artiq/gateware/targets/kasli.py b/artiq/gateware/targets/kasli.py
index 8fbaa0ec1..904464cbf 100755
--- a/artiq/gateware/targets/kasli.py
+++ b/artiq/gateware/targets/kasli.py
@@ -685,7 +685,7 @@ class _MasterBase(MiniSoC, AMPSoC):
     }
     mem_map.update(MiniSoC.mem_map)
 
-    def __init__(self, rtio_clk_freq=150e6, **kwargs):
+    def __init__(self, rtio_clk_freq=125e6, **kwargs):
         MiniSoC.__init__(self,
                          cpu_type="or1k",
                          sdram_controller_type="minicon",
@@ -834,7 +834,7 @@ class _SatelliteBase(BaseSoC):
     }
     mem_map.update(BaseSoC.mem_map)
 
-    def __init__(self, rtio_clk_freq=150e6, **kwargs):
+    def __init__(self, rtio_clk_freq=125e6, **kwargs):
         BaseSoC.__init__(self,
                  cpu_type="or1k",
                  sdram_controller_type="minicon",