I installed KVM on centos 6 dedicated server but the Download/Upload speed was very slow. The operating system on KVM is Windows XP. Download/Upload speed on Centos 6 is faster 10 times than on KVM. I also installed virtual box just to check whether the problem comes from KVM but it appeared that Virtual Box Download/Upload speed was slower than KVM. I also tried it on Ubuntu 12.04 server and the same thing happened. I read several tutorials on how to fix that but no one of them worked. This is a screenshot of my host device and device model http://i.imgur.com/Wu5WJUx.jpg. If i change the host device or the device model; Internet doesn't work on KVM.