 <p>What version of Android are you testing with? Can you adb shell in and see what these settings are (when you're on wifi)?</p> <pre><code>cat /proc/sys/net/ipv4/tcp_rmem cat /proc/sys/net/ipv4/tcp_wmem </code></pre> <p>And then if they are low (something like "4092 8760 11680"), then try setting them to larger values:</p> <pre><code>sudo echo "524288,1048576,2097152" &gt; /proc/sys/net/ipv4/tcp_rmem sudo echo "262144,524288,1048576" &gt; /proc/sys/net/ipv4/tcp_wmem </code></pre> <p>Then try your test again.</p> <p>This could be from a bug where the wifi buffers were being set too small in some cases (<a href="https://code.google.com/p/android/issues/detail?id=64706" rel="nofollow">https://code.google.com/p/android/issues/detail?id=64706</a>).</p>