[Networking problem] Downloading/uploading speed through a router to two computers

[dice4321]

I just replaced my crappy DSL modem with a new Comcast modem (30mb/s Down, and 5 mb/s Up)(yay!) and connected it to a router(linksys e1000). Tested at seperate times, Computer A is closest to the router and gets 30mb/s down and 5mb/s up while computer B is alot farther than the router and gets 20 mb/s down and 0.5 mb/s up, but when I plug Computer B's ethernet cable directly into the comcast modem it gets 30mb/s Down and 5 mb/s Up. I'v tried two different routers now and computer B still has different speeds as computer A. How do I make it so they both have the same speed?

Computer A (older)(30mb/s down and 5mb/s):

Ethernet cable - 1 feet from router
Cable type: CAT V
Motherboard: unknown, really old motherboard(uses ddr2 ram that old)~

Computer B (newer)(16 mb/s down and 0.5 mb/s up):

Ethernet cable - 15 feet from router
Cable type: CAT V
Motherboard: ASRock Z77 Extreme4 ATX LGA1155
Lan driver has also been updated top the current version

Sometimes when computer A downloads something, Computer B gets high ping.

 

[hang-the-9]

Try testing speeds with only one of the computers attached. It almost sounds like you are having collitions with them on the network since if you bypass the router (and you tried two to rule out a port/router issue) it works fine.

 

[dice4321]

Try testing speeds with only one of the computers attached. It almost sounds like you are having collitions with them on the network since if you bypass the router (and you tried two to rule out a port/router issue) it works fine.

I still get the same problem even if the modem and Computer B are the only two cables connected the the router.

 

[hang-the-9]

Have you swapped network cables for the PC to router connection? You said it worked fine when connected to the modem directly, could you be using a different cable when you tried that?

 

[dice4321]

Have you swapped network cables for the PC to router connection? You said it worked fine when connected to the modem directly, could you be using a different cable when you tried that?

mmm no... I used the same cables when I connected Computer B directly to the modem, and just a while ago, I disconnected all the connection except Computer B's ethernet cable to the router(with the exception of the modem) and still got 20 mb/s down and 0.5 mb/s up. Could it be the router is not liking my Computer B's connection?

 

[hang-the-9]

Since you have tried two different routers, doubt its the router, and since this worked with no issues on the modem, the computer network card looks to be OK as well. You can try getting a new network card, or maybe try a different cable.