proftpd slows after 1.4 gb

[bronxbuoy]

<ignore this thread - a disk hardware problem was found>

I installed proftpd 1.3.0 on a freshly installed Ubuntu feisty system. The server would not start under inetd so I configured it as standalone. From a Windows machine I did a binary get of a 7GB file. The throughput was reasonable until 1,429,200,896 bytes were transferred and then the throughput went way down. Using ethereal I could see that proftpd took 20 second pauses after a client acknowledgment and after each small transfer of 4, 8, or 16K spread across several packets. I got exactly the same behavior when I used a Solaris client on a Sun-Sparc workstation. Any ideas what is going on?