Comment 9 for bug 288948

Hello there! I have exactly the same problem.
According to iperf, my computer has an upload speed of about 4MBits / sec. That means about 500Kbytes/sec. However, all other computers have an upload speed of about 10 Mbits/sec.

The interesting thing is that download speed is right where it should be, 10 Mbits/sec. Perhaps this is because acknowledging the packets when they arrive takes far less bandwidth than sending them?

For what it's worth, I'm running a Linksys WRT54G Wireless G network. My surrounding environment is pretty crowded with other networks, but it's interesting because other hosts do not experience this slowdown.

To show that this is a wireless issue, I used iperf to do a little digging in different network configurations. The numbers are from memory, but I believe they're reasonably accurate.
WPA2, wireless: Up: ~4MBit/s, down: ~10Mbit/s
Moving right next to the router: Up: ~7Mbit/s, down: ~11Mbit/s
Open wireless: Up: ~7Mbit/s, down: ~12Mbit/s
Hardwired to the router, all other hosts wireless: Up: ~24Mbit/s, down: ~26Mbit/s

If somebody'd like, I can re-run the tests and give you exact results.