New Ethernet, New PC, 1.2 MB/sec? Please help!!

[SNMVPTK]

So just today I installed a 100 foot ethernet cable into my new PC, I plugged it into the back of the router, and I gained a connection. However, I tried to download games on Steam, and it was less than 1.5 Megabytes per second, weaker than my wifi! I don't think that the Ethernet should be going that slow. I have no idea what to do, I've even plugged the cable into different ports, and tried to reset the router. I've even changed the link speed to 1.0 Gb per sec. Is it my router's fault? Help!

 

[popatim]

lets start with the basics, the cable itself will have which category it is, look for cat3, cat4, cat5 or 5e, cat6... let us know which category the cable is.