I have had my main computer CABLE-connected to Internet for several years now with very high connection speed. When I recently bought a 2nd home computer I was förced to buy a LAN/wireless router to be able to connect both PCs to the Internet.
The new 2nd computer is then wireless-connected to the router (with lower speed, I don't care) and my first main computer connected to one of the LAN-ports of the router. In this way I thought I would get about the same connection speed. But to my surprise/disappointment the speed I get is several times slower!!.
Is there any way to have both computers connected (one wireless, one LAN) NOT spoiling the speed of my main computer? Thank you!

How are you determining sppeeds and what are the speeds ??

Router WAN
Internet PC
Internet WiFi PC

Do a internet speed test with the pc connected to the modem and then connected to the router. Post the results.

Imagine the power of knowing how to internet search
http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/FindInfo.html

I can clearly see the speed while downloading files in BitComet.
If I connect directly to the Internet I have about 500 kB/s downloading speed.
If I connect through the routers LAN-port I only get about 100 kB/s. About 5 times slower!!

Any device will slow the speed down a bit. You shouldn't notice it. Start with above, also see the routers log's, and look at your network settings. Might have to add in the router as a dns entry or add your isp's as extra dns to the nic card settings. Could also be a bad autoconfig, poor connection, poor or wrong cable.
Could be an odd setup or something to do with your isp. We can't tell about how you connect. Do you have a cable modem or adsl modem?

I read it wrong and answer it wrong too. So get off my case you peanut.

Another question is if the router is supposed to by-pass full speed when the connection computer-router is on the LAN-port of the router (not wireless)!?

No, I have neither cable modem or adsl modem, I do have cable connection.

Do as wanderer suggested. Run a bandwidth speed test (google that phrase and select the "speakeasy" site) both plugged into the router and directly into the modem from your PC and post the results here

A soho router can only work so fast. It is not the greatest thing sold. They do work fine for most people. Even a 10M lan connection is rather fast by internet standards.

Start doing some tests, looking at some configs. See task manager network speed to be sure you don't have some odd overhead on top of the download speed.

I read it wrong and answer it wrong too. So get off my case you peanut.

Here result of the Speakeasy test:
Direct connection:
Download Speed: 8293 kbps (1036.6 KB/sec transfer rate)
Upload Speed: 4124 kbps (515.5 KB/sec transfer rate)

Through Router:
Download Speed: 2528 kbps (316 KB/sec transfer rate)
Upload Speed: 2015 kbps (251.9 KB/sec transfer rate)

How is your nic card set for speed and duplex ?

My NIC "Link speed/Duplex mode" is set to: Autonegotiation.

Well, that is very odd that there is a difference like that.

What model SOHO router did you buy?

Is the PC you tested with connected to the router via wireless or is it plugged directly in? If wireless, try it with the PC plugged directly into the router and see if the bandwidth tests improve.

My router is Netgear WGR614.
The Router specification for the LAN-ports is: LAN - 10/100 Mbps/s (auto-sensing).
The PC is directly connected to one of the 4 LAN-ports of the router. So I don't understand why speed has to be so low!

Log on to router's web interface, look at the logs.

I read it wrong and answer it wrong too. So get off my case you peanut.

This is the Log.
It doesn't tell me much about why the connection is so much slower (!!??)

[Admin login] from source 192.168.1.2, Sunday, Mar 23,2008 11:55:51
[Service blocked: ICMP_echo_req] from source 85.241.138.237, Sunday, Mar 23,2008 11:55:24
[Internet connected] IP address: 213.112.87.8, Sunday, Mar 23,2008 11:55:01
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:32:25
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:29:12
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:26:52
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:25:49
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:25:36
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 11:25:20
[Internet connected] IP address: 213.112.87.8, Sunday, Mar 23,2008 11:25:01
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro3 Sunday, Mar 23,2008 11:18:29
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro\ Sunday, Mar 23,2008 11:06:22
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droV Sunday, Mar 23,2008 11:06:16
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droS Sunday, Mar 23,2008 11:06:13
[Service blocked: ICMP_echo_req] from source 66.227.151.20, Sunday, Mar 23,2008 11:05:01
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droû Sunday, Mar 23,2008 11:04:46
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droõ Sunday, Mar 23,2008 11:04:40
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droò Sunday, Mar 23,2008 11:04:37
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro Sunday, Mar 23,2008 11:02:58
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droŠ Sunday, Mar 23,2008 11:02:52
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro‡ Sunday, Mar 23,2008 11:02:49
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro, Sunday, Mar 23,2008 11:01:19
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro& Sunday, Mar 23,2008 11:01:13
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro# Sunday, Mar 23,2008 11:01:10
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÈ
 Sunday, Mar 23,2008 10:59:39
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÂ
 Sunday, Mar 23,2008 10:59:33
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro¿
 Sunday, Mar 23,2008 10:59:30
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is drod
 Sunday, Mar 23,2008 10:57:59
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro^
 Sunday, Mar 23,2008 10:57:53
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro[
 Sunday, Mar 23,2008 10:57:50
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro
 Sunday, Mar 23,2008 10:56:23
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÿ Sunday, Mar 23,2008 10:56:17
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droü Sunday, Mar 23,2008 10:56:14
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 10:56:08
[Internet connected] IP address: 213.112.87.8, Sunday, Mar 23,2008 10:55:00
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro¡ Sunday, Mar 23,2008 10:54:43
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro› Sunday, Mar 23,2008 10:54:37
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro˜ Sunday, Mar 23,2008 10:54:34
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro< Sunday, Mar 23,2008 10:53:02
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro6 Sunday, Mar 23,2008 10:52:56
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro3 Sunday, Mar 23,2008 10:52:53
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÜ Sunday, Mar 23,2008 10:51:27
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 10:51:23
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÖ Sunday, Mar 23,2008 10:51:21
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droÓ Sunday, Mar 23,2008 10:51:18
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro} Sunday, Mar 23,2008 10:49:52
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is drow Sunday, Mar 23,2008 10:49:46
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is drot Sunday, Mar 23,2008 10:49:43
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 10:49:26
[UPnP set event: Public_UPNP_C3] from source 192.168.1.2, Sunday, Mar 23,2008 10:48:56
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro Sunday, Mar 23,2008 10:48:10
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro Sunday, Mar 23,2008 10:48:04
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro Sunday, Mar 23,2008 10:48:01
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro¶
 Sunday, Mar 23,2008 10:46:33
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro°
 Sunday, Mar 23,2008 10:46:27
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro­
 Sunday, Mar 23,2008 10:46:24
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droU
 Sunday, Mar 23,2008 10:44:56
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droO
 Sunday, Mar 23,2008 10:44:50
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droM
 Sunday, Mar 23,2008 10:44:47
[Service blocked: ICMP_echo_req] from source 208.81.184.4, Sunday, Mar 23,2008 10:44:17
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droõ  Sunday, Mar 23,2008 10:43:19
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droï  Sunday, Mar 23,2008 10:43:13
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is droì  Sunday, Mar 23,2008 10:43:10
[Self2WAN ICMP type b Detected!] To prevent from revealing router's activity, this packet is dro”  Sunday, Mar 23,2008 10:41:42

I see nothing in the log to explain this issue and to be honest, it shouldn't be happening. Considering your internet connection is slower than 10/100 Mbps your connection rate from a client plugged into the router should be the same as if it is plugged directly into the modem.

At this point my best suggestion is to get ahold of Netgear's support people and explain your problem to them. There may be something wrong with the router or a setting you have to change and they'll be the people best able to help you.

Thank you anyway,
I will do a try,
I wonder though if that will give any result!