diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -2813,7 +2813,7 @@
 							tcp_sack_adjust(tp);
 					tp->snd_cwnd +=
 					    (tp->t_dupacks - tp->snd_limited) *
-					    maxseg;
+					    maxseg - tcp_sack_adjust(tp);
 					/*
 					 * Only call tcp_output when there
 					 * is new data available to be sent
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -292,7 +292,8 @@
 	len = 0;
 	p = NULL;
 	if ((tp->t_flags & TF_SACK_PERMIT) &&
-	    (IN_FASTRECOVERY(tp->t_flags) || SEQ_LT(tp->snd_nxt, tp->snd_max)) &&
+	    (IN_FASTRECOVERY(tp->t_flags) ||
+	     (SEQ_LT(tp->snd_nxt, tp->snd_max) && (tp->t_dupacks >= tcprexmtthresh))) &&
 	    (p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
 		int32_t cwin;