diff --git a/tests/eth_mac/Makefile b/tests/eth_mac/Makefile
index c8be4f9..e2c028b 100644
--- a/tests/eth_mac/Makefile
+++ b/tests/eth_mac/Makefile
@@ -31,6 +31,14 @@ TOPLEVEL = $(DUT)
 MODULE   = $(DUT)
 VERILOG_SOURCES += $(DUT).v
 
+# module parameters
+export PARAM_PTP_TS_WIDTH := 96
+export PARAM_PTP_TAG_WIDTH := 16
+export PARAM_AXIS_DATA_WIDTH := 64
+export PARAM_AXIS_KEEP_WIDTH := $(shell expr $(PARAM_AXIS_DATA_WIDTH) / 8 )
+export PARAM_AXIS_TX_USER_WIDTH := $(shell expr $(PARAM_PTP_TAG_WIDTH) + 1 )
+export PARAM_AXIS_RX_USER_WIDTH := $(shell expr $(PARAM_PTP_TS_WIDTH) + 1 )
+
 ifeq ($(SIM), icarus)
 	PLUSARGS += -fst
 
diff --git a/tests/eth_mac/test_eth_mac.py b/tests/eth_mac/test_eth_mac.py
index 63b09dc..3c255e3 100644
--- a/tests/eth_mac/test_eth_mac.py
+++ b/tests/eth_mac/test_eth_mac.py
@@ -28,6 +28,7 @@ import logging
 import os
 
 import cocotb_test.simulator
+import pytest
 
 import cocotb
 from cocotb.clock import Clock
@@ -45,8 +46,20 @@ class TB:
         self.log = logging.getLogger("cocotb.tb")
         self.log.setLevel(logging.DEBUG)
 
-        cocotb.start_soon(Clock(dut.tx_clk, 6.4, units="ns").start())
-        cocotb.start_soon(Clock(dut.rx_clk, 6.4, units="ns").start())
+        if len(dut.tx_axis_tdata) == 8:
+            clk_period = 8
+        elif len(dut.tx_axis_tdata) == 32:
+            clk_period = 3.102
+        elif len(dut.tx_axis_tdata) == 64:
+            if speed == 25e9:
+                clk_period = 2.56
+            else:
+                clk_period = 6.206
+        elif len(dut.tx_axis_tdata) == 512:
+            clk_period = 3.102
+
+        cocotb.start_soon(Clock(dut.tx_clk, clk_period, units="ns").start())
+        cocotb.start_soon(Clock(dut.rx_clk, clk_period, units="ns").start())
 
         self.mac = EthMac(
             tx_clk=dut.tx_clk,
@@ -157,12 +170,21 @@ def incrementing_payload(length):
 
 if cocotb.SIM_NAME:
 
+    if len(cocotb.top.tx_axis_tdata) == 8:
+        speed = [100e6, 1e9]
+    elif len(cocotb.top.tx_axis_tdata) == 32:
+        speed = [10e9]
+    elif len(cocotb.top.tx_axis_tdata) == 64:
+        speed = [10e9, 25e9]
+    elif len(cocotb.top.tx_axis_tdata) == 512:
+        speed = [100e9]
+
     for test in [run_test_tx, run_test_rx]:
 
         factory = TestFactory(test)
         factory.add_option("payload_lengths", [size_list])
         factory.add_option("payload_data", [incrementing_payload])
-        factory.add_option("speed", [10e9, 1e9])
+        factory.add_option("speed", speed)
         factory.generate_tests()
 
 
@@ -171,7 +193,8 @@ if cocotb.SIM_NAME:
 tests_dir = os.path.dirname(__file__)
 
 
-def test_eth_mac(request):
+@pytest.mark.parametrize("data_width", [8, 32, 64, 512])
+def test_eth_mac(request, data_width):
     dut = "test_eth_mac"
     module = os.path.splitext(os.path.basename(__file__))[0]
     toplevel = dut
@@ -182,6 +205,13 @@ def test_eth_mac(request):
 
     parameters = {}
 
+    parameters['PTP_TS_WIDTH'] = 96
+    parameters['PTP_TAG_WIDTH'] = 16
+    parameters['AXIS_DATA_WIDTH'] = data_width
+    parameters['AXIS_KEEP_WIDTH'] = parameters['AXIS_DATA_WIDTH'] // 8
+    parameters['AXIS_TX_USER_WIDTH'] = parameters['PTP_TAG_WIDTH']+1
+    parameters['AXIS_RX_USER_WIDTH'] = parameters['PTP_TS_WIDTH']+1
+
     extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}
 
     sim_build = os.path.join(tests_dir, "sim_build",
diff --git a/tests/eth_mac/test_eth_mac.v b/tests/eth_mac/test_eth_mac.v
index cbbb39b..f546222 100644
--- a/tests/eth_mac/test_eth_mac.v
+++ b/tests/eth_mac/test_eth_mac.v
@@ -29,29 +29,37 @@ THE SOFTWARE.
 /*
  * Ethernet MAC model test
  */
-module test_eth_mac
+module test_eth_mac #
 (
-    inout  wire        tx_clk,
-    inout  wire        tx_rst,
-    inout  wire [63:0] tx_axis_tdata,
-    inout  wire [7:0]  tx_axis_tkeep,
-    inout  wire        tx_axis_tlast,
-    inout  wire [16:0] tx_axis_tuser,
-    inout  wire        tx_axis_tvalid,
-    inout  wire        tx_axis_tready,
-    inout  wire [95:0] tx_ptp_time,
-    inout  wire [95:0] tx_ptp_ts,
-    inout  wire [15:0] tx_ptp_ts_tag,
-    inout  wire        tx_ptp_ts_valid,
+    parameter PTP_TS_WIDTH = 96,
+    parameter PTP_TAG_WIDTH = 16,
+    parameter AXIS_DATA_WIDTH = 64,
+    parameter AXIS_KEEP_WIDTH = (AXIS_DATA_WIDTH/8),
+    parameter AXIS_TX_USER_WIDTH = PTP_TAG_WIDTH+1,
+    parameter AXIS_RX_USER_WIDTH = PTP_TS_WIDTH+1
+)
+(
+    inout  wire                           tx_clk,
+    inout  wire                           tx_rst,
+    inout  wire [AXIS_DATA_WIDTH-1:0]     tx_axis_tdata,
+    inout  wire [AXIS_KEEP_WIDTH-1:0]     tx_axis_tkeep,
+    inout  wire                           tx_axis_tlast,
+    inout  wire [AXIS_TX_USER_WIDTH-1:0]  tx_axis_tuser,
+    inout  wire                           tx_axis_tvalid,
+    inout  wire                           tx_axis_tready,
+    inout  wire [PTP_TS_WIDTH-1:0]        tx_ptp_time,
+    inout  wire [PTP_TS_WIDTH-1:0]        tx_ptp_ts,
+    inout  wire [PTP_TAG_WIDTH-1:0]       tx_ptp_ts_tag,
+    inout  wire                           tx_ptp_ts_valid,
 
-    inout  wire        rx_clk,
-    inout  wire        rx_rst,
-    inout  wire [63:0] rx_axis_tdata,
-    inout  wire [7:0]  rx_axis_tkeep,
-    inout  wire        rx_axis_tlast,
-    inout  wire [96:0] rx_axis_tuser,
-    inout  wire        rx_axis_tvalid,
-    inout  wire [95:0] rx_ptp_time
+    inout  wire                           rx_clk,
+    inout  wire                           rx_rst,
+    inout  wire [AXIS_DATA_WIDTH-1:0]     rx_axis_tdata,
+    inout  wire [AXIS_KEEP_WIDTH-1:0]     rx_axis_tkeep,
+    inout  wire                           rx_axis_tlast,
+    inout  wire [AXIS_RX_USER_WIDTH-1:0]  rx_axis_tuser,
+    inout  wire                           rx_axis_tvalid,
+    inout  wire [PTP_TS_WIDTH-1:0]        rx_ptp_time
 );
 
 endmodule