diff --git a/test/perf/passt_udp b/test/perf/passt_udp
index 8c1b67f..e351987 100644
--- a/test/perf/passt_udp
+++ b/test/perf/passt_udp
@@ -123,7 +123,7 @@ iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -b 4G
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 4.0 5.0
 ns	ip link set dev lo mtu 65520
-iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -b 6G
+iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -b 4G
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 5.0 5.5
 
@@ -162,7 +162,7 @@ iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -b 4G
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 4.0 5.0
 ns	ip link set dev lo mtu 65520
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -b 6G
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -b 4G
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 5.0 5.5