internet connection speed problem

hello, i have extreme speed internet though Time Warner Cable, i am useing a DOCSIS 3 cablemodem/wiFi router, the tech support guy recomended that i come here because i am getting the download/upload speeds on my router/modem, we are suppose to get. 30 megs download and up to 5 megs upload.

My problem is i am getting my download speeds and upload speeds that i am suppose to be getting on my wifes computer that is right next to the modem. but mine which the wire goes through the wall , up the wall, over my ceiling , down the wall and then to my computer, my download speed is only maybe 8.40 down and i am hitting the upload speed.

i dont know what to do, i changed CAT5 cords ,that did nothing.

this is a brand new computer, i built it my self. the motherboard is a sabertooth Z77 it , the ethernet conection is built onto the mother board, and again i am wired not wireless.

mike.

 

ok so i took my PC in and pluged it all in next to my wife's PC and low and Behold i am getting the speeds i am suppose to be getting in there. SO i guess i found the problem. ty anyways , Mike.:-o