I have a Linksys WRT54G and I pay for a 12Mbps connection. I've been testing my connection using speedtest.net for many days and always get 8Mbps.

I called the support and they told me to bypass the router and test. I did it and got 16Mbps (much more than I pay for), so I thought "this guy just changed my speed so can he blame my router", and he blamed it. But to my surprise, everytime I bypass the router I get 16Mbps and when I use the router I get 8Mbps.

Is this guy trolling me somehow (configuring the VOIP-modem-stuff to different profiles depending o the MAC address connecting to it) or is my router a POS? How can I find out?

I don't know what's the thing the router connects to, it's a kind of VOIP adapter; the link is this one, but unfortunately I don't think you'll understand because it's in Portuguese. I know they can remotely connect to it, that's the origin of my conspiracy theory :)

I just tested wired to the router and got 10Mbps (and still 8Mbps on wifi and 16Mbps without router) O_o

I'm 5cm away from my router, so no obstacles to interfere, right?

------ UPDATE -------

It's a WRT54G V8, I'm using firmware v8.00.7 (will install 8.00.8 tomorrow, but I saw that it's only a minor fix to UPnP denial of service security vulnerability).

Results:

IPerf LAN-LAN: 80Mbps

IPerf LAN-WLAN: 19Mbps (therefore we can ignore wireless issues/settings)

I wasn't able to make the (W)LAN-WAN NAT-enabled test with IPerf, I get a connection refused error. I'm not sure if did it right: ran in server mode, configured router to forward that port to my IP and tried to connect to my internet IP that got from this site.

I don't think there is a way to disable NAT using this firmware.

Question:

Let's suppose it's an underpowered hardware issue. Is it right to assume that custom firmwares could resolve the issue because they are possibly better implemented and would make better use of the router resources?

I couldn't find any references pointing to wired performance improvements with the use of custom firmware.