If you're using a KVM and not getting appropriate network speed (like 100Mbps when you're supposed to get 1Gbps) - you may try the following
open /etc/sysctl.conf in your server and append the following lines
net.core.rmem_max=16777216
net.core.wmem_max=16777216
net.ipv4.tcp_rmem=4096 87380 16777216
net.ipv4.tcp_wmem=4096 65536 16777216
Now in terminal run the following command
sysctl -p
Now check network speed again. Here is how it went for me
#Stock Options
Download speed from CacheFly: 8.29MB/s
Download speed from Coloat, Atlanta GA: 2.31MB/s
Download speed from Softlayer, Dallas, TX: 3.45MB/s
After sysctl.conf edit
Download speed from CacheFly: 51.2MB/s
Download speed from Coloat, Atlanta GA: 19.8MB/s
Download speed from Softlayer, Dallas, TX: 53.0MB/s
Download speed from Linode, Tokyo, JP: 10.6MB/s
Download speed from i3d.net, Rotterdam, NL: 5.12MB/s
Download speed from Leaseweb, Haarlem, NL: 14.2MB/s
Download speed from Softlayer, Singapore: 8.87MB/s
Download speed from Softlayer, Seattle, WA: 36.7MB/s
Download speed from Softlayer, San Jose, CA: 33.6MB/s
Download speed from Softlayer, Washington, DC: 76.5MB/s