diff -urN gpxe-0.9.7/src/drivers/net/e1000/e1000.c gpxe-0.9.7-e1000fix/src/drivers/net/e1000/e1000.c
--- gpxe-0.9.7/src/drivers/net/e1000/e1000.c	2009-03-01 21:23:42.000000000 -0500
+++ gpxe-0.9.7-e1000fix/src/drivers/net/e1000/e1000.c	2009-08-21 21:13:59.000000000 -0400
@@ -586,6 +586,7 @@
 
 	/* Write new tail to NIC, making packet available for transmit
 	 */
+	wmb();
 	E1000_WRITE_REG ( hw, TDT, adapter->tx_tail );
 
 	return 0;