I just purchased an iPod Touch. I am having a lot of trouble with its speeds on my Tenda W311R, but it has no speed problems on my neighbor's Netgear router.

It will connect and authenticate to my network, but the Speed Test app from speedtest.net shows rates near 20-50 kbps.
If I run the speed test immediately after powering the iPod on, it will get speeds of 10-20 Mbps, like it should - but the speeds slow down to the kbps range abut 10-15 seconds afterward.

I get the same behavior with encryption and without encryption, and regardless of N, G, or B compatibility settings in the router.

I've tried rebooting the iPod and resetting the network settings, but it's still slow.

I've tried pinging the iPod from another computer, and it shows about 40% packet loss:

$ ping 192.168.0.111
PING 192.168.0.111 (192.168.0.111): 56 data bytes
64 bytes from 192.168.0.111: icmp_seq=0 ttl=64 time=14.188 ms
64 bytes from 192.168.0.111: icmp_seq=1 ttl=64 time=11.556 ms
64 bytes from 192.168.0.111: icmp_seq=2 ttl=64 time=5.675 ms
64 bytes from 192.168.0.111: icmp_seq=3 ttl=64 time=5.721 ms
Request timeout for icmp_seq 4
64 bytes from 192.168.0.111: icmp_seq=5 ttl=64 time=6.491 ms
Request timeout for icmp_seq 6
64 bytes from 192.168.0.111: icmp_seq=7 ttl=64 time=8.065 ms
Request timeout for icmp_seq 8
Request timeout for icmp_seq 9
Request timeout for icmp_seq 10
64 bytes from 192.168.0.111: icmp_seq=11 ttl=64 time=9.605 ms

Signal strength is good - I'm never more than 20 feet from my access point, and it exhibits the same behavior if I'm standing next to the router.

It works just well enough to receive text, but videos don't work at all. App downloads are hit and miss.

I've tweaked just about all of the settings I can see to tweak, and I'm at a loss.
I have also been searching Google for the past three days, all to no avail.

Any suggestions?