My ISP is Optonline and I have their boost service which advertises a maximum download speed of 30 Mbps and something smaller on the upload side. When I connect my PowerBook directly to the cable modem the speed test that Optonline provides shows a download speed of about 27 Mbps which is quite good. I get similar results with other speed test sites. Now the problem.
I connected the PB via an ethernet cable to a LAN port on my Netgear WPN824 wireless router. I reran the speed test and got a download speed of about 11 Mbps (I turned the Airport off during this test). Next, I turned the Airport on, disconnected from the LAN port and again ran the speed test. This time the download speed was about 9 Mbps. So clearly the router is a bottleneck.
I searched the forums here and tried stuff like changing the MTU and the channel the router broadcasts on but none of these things make any difference.
While some reduction in throughput is to be expected when operating wirelessly it shouldn't drop so dramatically even when the Mac is connected directly to the router (27 Mbps to 11 Mbps). Has anyone else experienced such sharp dropoffs? Is there a better wireless router? Better settings for this router?