[ATPTourFan]

Ever since I got DSL, I have been disappointed with the performance compared to my previous cable modem connection (which I had to drop because of poor coax in my condo). I'm paying for 1.5Mb downstream for DSL but I never realized speed faster than around 92KB/sec. I figured I was too far from the switch station. All speeds are measured with Activity Monitor's Network panel.

The DSL modem, when I go into it's 192.168.1.1 console, reports a 800kb/sec down, 128kb up connection (which is in line with my experienced speeds). Today, just out of chance, I plugged my PowerBook G4 into the DSL modem directly. It still shows the 800/128 connection, yet my internet speed doubled to 180KB/sec. I was amazed so I went to lots of fast webservers like Apple's QT Trailers, etc. Sure enough, all different sites were working at double speed when I bypassed the router.

I went to plug the ethernet cable back into the router and I connected my PB to it via Ethernet (no WiFi), and instantly the connection is back to the half speed. There's nothing special going on in the router. I reset it to defaults and only added my PPPoE info. Still just half speed.

I normally run the router (which has the latest firmware) with WPA/PSK on a WiFi channel that's not cluttered. As I mentioned the half speed is realized with Ethernet connections as well as WiFi, so it's not a bad connection or interference issue.

Any ideas?

[ghporter]

What router are you using? A LOT of wireless routers require some tweaking to get them to work right-and I think I know exactly what tweak you need. Cable connections use a Maximum Transmission Unit (MTU) of 1500, which sets the largest data packet size the computer can send. DSL uses a somewhat smaller number: 1492 typically. If your router is not told to use a smaller MTU, your larger packets will be fragmented, causing multiple retransmissions and typically dropping potential speed by about 50%. Your PowerBook works better connected directly to the modem because it automatically detects the appropriate MTU (through a process called MTU Discovery which I believe is enabled by default in most OS X installations). The router's browser-based configuration system should offer a tool to change its MTU setting. I can't help more without knowing what router you have.

You should also be aware that most DSL packages provide "up to" a stated speed, and that it can be less based on a huge number of factors, distribution cables and building wiring being major factors.