WRT54GC 100Mbps wired gives 37Mbps

Question

I may be missing something obvious here for which I apologise in advance, but I've searched through these forums and the technical specifications for the WRT54GC router as far as I can understand them, and I'm still not sure why I'm getting the results I have.
I'm living in South Korea and have a 100Mbps connection in my apartment with LG Powercom, my ISP. When I connect my computer directly to the Internet I get upload and download speeds of approximately 93Mbps when testing a 100 megabyte transfer against LG's servers - which equals around 11.6MB/s.
http://img215.imageshack.us/img215/9938/internetnorouterfp6.png
However, when I connect through the router (wired, not wirelessly), the speed is consistently around 38Mbps, or 4.8MB/s. The test results hold true for external download tests.
http://img215.imageshack.us/img215/6310/internetrouterxm3.png
I understand that the wireless speed is 54Mbps (802.11g) but I thought the router should be capable of 100Mbps wired (100Base-TX). I know I'll never actually reach 100 in reality but I'm losing 50Mbps connecting through the router. I upgraded it to the latest version of the firmware (v1.05.7), but the results are consistent on the two computers I have running through the router.
Have I misunderstood the router's capabilities and is it limited to a maximum of 54Mbps both wirelessly and wired, and 38Mbps is about what I could reasonably expect when wired? Also, if I am stuck at 38Mbps, could anyone recommend a wired or wireless router than can actually manage 100Mbps wired?

Answer 1

With the WRT54GC router, only the switch is designed to run at 10/100 speeds.  So if you did a file transfer across your LAN, from one wired computer to another wired computer, you would get a 100 Mbps connection, and a data transfer rate of about 93 Mbps, which is about the limit for a 100 Mbps wired connection.
On the other hand, data passing through the Internet port of the WRT54GC must be processed by the router (which is a small computer).  The incoming data must pass through the router's firewall, get port forwarded (if this feature is used), get linked to the correct computer, and then must be directed to the appropriate wired port or out the wireless.  All this takes router processing power.  The bottom line is that it won't run at 100 Mbps.
When I checked on your router, its maximum speed (Intenet port to wired LAN port) is rated at 47 Mbps, only a little more than the 38 Mbps that you reported.
You should also be aware that a 54 Mbps wireless connection will not transfer data at 54 Mbps.  Under ideal lab conditions (read: not in your home) it can do about 25 Mbps of data transfer.  Most home users are lucky to get 10 Mbps of data transfer.
To get the higher router speeds that you crave, you will need to buy one of the newer, and more expensive routers, such as the WRT350N or the WRT600N.   According to one web site I checked, these models have a (WAN port to wired LAN port) speed of over 150 Mbps.  For fast wireless speed, you will also need a wireless n adapter.  This ideally will give you a wireless connection of 270 to 300 Mbps, and a wireless data transfer speed of 20 to 70 Mbps.
Hope this helps.
Message Edited by toomanydonuts on 02-05-2008 12:22 AM