Hyper-V 2012 R2 Generation 2 Linux VM’s
Microsoft is starting to support Hyper-V Generation 2 VM’s for Linux. This alone would speed up any compatible Linux OS quite a bit by opening up some of the disk access bottlenecks that Generation 1 VM’s suffer from. This performance bottleneck was caused by the VM only being able to boot from a virtual IDE disk. On a Hyper-V 2012 R2 Generation 2 Linux VM’s you are able to take advantage of booting from a virtual SCSI disk and if the OS supports it you can also enable UEFI boot mode which makes boot times even faster.
http://technet.microsoft.com/en-us/library/dn282285.aspx
http://technet.microsoft.com/en-us/library/dn531030.aspx