diff --git a/src/gateware/kasli_soc.py b/src/gateware/kasli_soc.py
index 51276308..d6325db2 100755
--- a/src/gateware/kasli_soc.py
+++ b/src/gateware/kasli_soc.py
@@ -187,9 +187,7 @@ class GenericMaster(SoCCore):
     mem_map.update(SoCCore.mem_map)
 
     def __init__(self, description, acpki=False):
-        sys_clk_freq = 800e6  # this is not set within SoCCore anymore, but rather - by SZL?
-                              # not sure if it should be ArmPLL/CPU/IoPLL freq - they differ slightly
-                              # necessary for GTX transceiver  
+        sys_clk_freq = 125e6
         rtio_clk_freq = 125e6 # should this be pulled from description? rtio freq isnt set
 
         self.acpki = acpki
@@ -331,9 +329,7 @@ class GenericSatellite(SoCCore):
     mem_map.update(SoCCore.mem_map)
 
     def __init__(self, description, acpki=False):
-        sys_clk_freq = 800e6  # this is not set within SoCCore anymore, but rather - by SZL?
-                              # not sure if it should be ArmPLL/CPU/IoPLL freq - they differ slightly
-                              # necessary for GTX transceiver  
+        sys_clk_freq = 125e6  
         rtio_clk_freq = 125e6  # same thing as with master - pulled from desc?
                                # will probably be replaced with rtio_config key as per #1735
 
diff --git a/src/gateware/zc706.py b/src/gateware/zc706.py
index b6be69a5..28466df1 100755
--- a/src/gateware/zc706.py
+++ b/src/gateware/zc706.py
@@ -269,9 +269,8 @@ class Master(ZC706):
     def __init__(self, **kwargs):
         ZC706.__init__(self, **kwargs)
 
-        sys_clk_freq = 800e6  # same as in Kasli-SoC - CPU freq set by SZL
-                              # again not sure if correct value
-
+        sys_clk_freq = 125e6
+        
         platform = self.platform
 
         self.comb += platform.request("sfp_tx_disable_n").eq(1)
@@ -373,8 +372,7 @@ class Satellite(ZC706):
 
     def __init__(self, **kwargs):
         ZC706.__init__(self, **kwargs)
-        sys_clk_freq = 800e6  # same as in Kasli-SoC - CPU freq set by SZL
-                              # again not sure if correct value
+        sys_clk_freq = 125e6
 
         platform = self.platform