Sorry for the delay, didn't find any time yesterday to do this.

Either way, I can't reproduce your results. Here's the benchmark results on my end:

$T=4  : 264 wallclock secs ( 3.80 usr + 2.09 sys =  5.89 CPU) -> 0.24 
+MByte/sec
$T=8  : 151 wallclock secs ( 5.31 usr + 1.89 sys =  7.20 CPU) -> 0.43 
+MByte/sec
$T=12 : 117 wallclock secs ( 6.55 usr + 2.41 sys =  8.95 CPU) -> 0.55 
+MByte/sec
$T=16 : 104 wallclock secs ( 7.73 usr + 2.83 sys = 10.56 CPU) -> 0.62 
+MByte/sec
$T=20 : 102 wallclock secs ( 8.36 usr + 2.80 sys = 11.16 CPU) -> 0.63 
+MByte/sec
$T=24 : 100 wallclock secs (10.11 usr + 3.00 sys = 13.11 CPU) -> 0.65 
+MByte/sec
$T=28 : 103 wallclock secs (11.89 usr + 3.02 sys = 14.91 CPU) -> 0.63 
+MByte/sec
$T=50 : 103 wallclock secs (18.89 usr + 4.30 sys = 23.19 CPU) -> 0.63 
+MByte/sec
[download]

Right now I'm thinking that the difference between us is either the power of my laptop, your router or just plain your internet connection.

Also, thanks for the suggestion, I'll forward it. :)