diff --git a/tb/eth/taxi_eth_mac_1g_gmii/test_taxi_eth_mac_1g_gmii.py b/tb/eth/taxi_eth_mac_1g_gmii/test_taxi_eth_mac_1g_gmii.py
index bd6c611..a34ec05 100644
--- a/tb/eth/taxi_eth_mac_1g_gmii/test_taxi_eth_mac_1g_gmii.py
+++ b/tb/eth/taxi_eth_mac_1g_gmii/test_taxi_eth_mac_1g_gmii.py
@@ -41,7 +41,7 @@ class TB:
         self.gmii_phy = GmiiPhy(dut.gmii_txd, dut.gmii_tx_er, dut.gmii_tx_en, dut.mii_tx_clk, dut.gmii_tx_clk,
             dut.gmii_rxd, dut.gmii_rx_er, dut.gmii_rx_dv, dut.gmii_rx_clk, speed=speed)
 
-        # the UUT tx_clk/rx_clk, which can cause problems in cocotb
+        # the UUT forwards tx_clk/rx_clk, which can cause problems in cocotb
         if speed == 1000e6:
             self.axis_source = AxiStreamSource(AxiStreamBus.from_entity(dut.s_axis_tx), dut.gtx_clk, dut.tx_rst)
             self.tx_cpl_sink = AxiStreamSink(AxiStreamBus.from_entity(dut.m_axis_tx_cpl), dut.gtx_clk, dut.tx_rst)
diff --git a/tb/eth/taxi_eth_mac_1g_rgmii/test_taxi_eth_mac_1g_rgmii.py b/tb/eth/taxi_eth_mac_1g_rgmii/test_taxi_eth_mac_1g_rgmii.py
index 9989e99..de5da61 100644
--- a/tb/eth/taxi_eth_mac_1g_rgmii/test_taxi_eth_mac_1g_rgmii.py
+++ b/tb/eth/taxi_eth_mac_1g_rgmii/test_taxi_eth_mac_1g_rgmii.py
@@ -38,8 +38,9 @@ class TB:
         self.rgmii_phy = RgmiiPhy(dut.rgmii_txd, dut.rgmii_tx_ctl, dut.rgmii_tx_clk,
             dut.rgmii_rxd, dut.rgmii_rx_ctl, dut.rgmii_rx_clk, speed=speed)
 
-        self.axis_source = AxiStreamSource(AxiStreamBus.from_entity(dut.s_axis_tx), dut.tx_clk, dut.tx_rst)
-        self.tx_cpl_sink = AxiStreamSink(AxiStreamBus.from_entity(dut.m_axis_tx_cpl), dut.tx_clk, dut.tx_rst)
+        # the UUT forwards tx_clk/rx_clk, which can cause problems in cocotb
+        self.axis_source = AxiStreamSource(AxiStreamBus.from_entity(dut.s_axis_tx), dut.gtx_clk, dut.tx_rst)
+        self.tx_cpl_sink = AxiStreamSink(AxiStreamBus.from_entity(dut.m_axis_tx_cpl), dut.gtx_clk, dut.tx_rst)
         self.axis_sink = AxiStreamSink(AxiStreamBus.from_entity(dut.m_axis_rx), dut.rx_clk, dut.rx_rst)
 
         self.rx_ptp_clock = PtpClockSimTime(ts_tod=dut.rx_ptp_ts, clock=dut.rx_clk)