Ventrilo Severely Degrading Network Performance

[NeoLojik]

Update: Solved. See [URL]http://www.ventrilo.com/forums/showpost.php?p=139277&postcount=17[/URL]

Good evening,

I've discovered that when the Ventrilo client is running and connected to a server, the machine it's running on has it's ethernet receive throughput cut by up to 85%.

I have 2 PC's on my desk here, let's call them PC1 and PC2.

PC1 runs Windows Vista 64bit, has all the latest drivers and updates from Microsoft. PC1 also runs the Ventrilo client (v3.0.5).

PC2 runs Windows XP 32bit. Again all drivers are the latest and it has all updates available.

Using iperf, a command-line network performance utility, I'm able to measure throughput both before and after launching Ventrilo. Showing the issue.

PC1 is acting as the iperf server, PC2 is the client. They are connected via a gigabit switch.

Without Ventrilo running:

C:\Users\Nexx\Desktop>iperf -s -w 128k
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size:  128 KByte
------------------------------------------------------------
[160] local 192.168.0.20 port 5001 connected with 192.168.0.21 port 3134
[188] local 192.168.0.20 port 5001 connected with 192.168.0.21 port 3135
[ ID] Interval       Transfer     Bandwidth
[188]  0.0-30.0 sec  1.65 GBytes   472 Mbits/sec
[160]  0.0-30.0 sec  1.65 GBytes   472 Mbits/sec
[SUM]  0.0-30.0 sec  3.29 GBytes   943 Mbits/sec

With Ventrilo running:

[164] local 192.168.0.20 port 5001 connected with 192.168.0.21 port 3136
[204] local 192.168.0.20 port 5001 connected with 192.168.0.21 port 3137
[ ID] Interval       Transfer     Bandwidth
[204]  0.0-30.0 sec   209 MBytes  58.4 Mbits/sec
[164]  0.0-30.0 sec   209 MBytes  58.4 Mbits/sec
[SUM]  0.0-30.0 sec   418 MBytes   117 Mbits/sec

Without Ventrilo running, or running but not connected, the actual throughput fluctuates by a couple of megabits each way. When Ventrilo is running the result is always -exactly- the same.

The issue is system-wide, it's not limited to iperf. When copying a file to PC1 the throughput drops from 65-70MB/sec to barely 12-13MB/sec when Ventrilo is running and connected.

I've also confirmed the issue with a friend of mine, who has spent weeks thinking there was something wrong with his gigabit network. He sees the exact same issue when Ventrilo is running and connected.

I have to wonder what on earth Ventrilo is doing to the networking stack to cause an 85-90% reduction in Rx traffic.

Hopefully someone from flagship will see this and look into the matter.