internet slower on desktop pc than other devices

here is an example of the speeds, both are wired via RJ45 to the same modem/router even wireless devices are getting a better connection. Really unsure where to start with this one so all help is appreciated. The difference is ~ 45 Mb/s

this pc:
http://www.speedtest.net/result/3983109967.png

Other pc:
http://www.speedtest.net/result/3983054207.png