In the last post I covered some of the basic differences between Gen1 and Gen2 VMs, today it’s time to dig a bit deeper. Let’s start with a quick recap of some of the things that were discussed last time.

First of all, the BIOS has been replaced with UEFI, which introduces a legacy free environment. Many of the devices that Gen1 VMs have emulated are now removed, and SCSI disk support has completely replaced IDE, including boot support. Also, the big one for me was the support for PXE in the synthetic network adapter, which offers big benefits in installation speed.

There are other enhancements in Hyper-V which I haven’t covered yet, and these include Hyper-V Manager connecting to VMs via Remote Desktop, which gives the benefit of a shared clipboard and audio redirection, and can allow the integration of devices such as smart card readers. This really helps to start overcoming some of the changes that occurred on the client side with XP Mode going away, and makes Hyper-V a bit more end user friendly.


You’ll notice a new option in the Integration Services which is Guest Services, which isn’t enable by default. Enabling this is what provides the ability to use RDP over VMBus, and it’s available in both Gen1 and Gen2 VMs.

Here’s a list of the hardware differences between the VM types and some of the benefits the new platform delivers.

Legacy Devices Removed

Replacement Devices


IDE Controller

Virtual SCSI Controller

Boot from VHDx (64TB max size, online resize)



Hot add/remove

Legacy BIOS

UEFI firmware

Secure Boot

Legacy NIC

Synthetic NIC

Network boot with IPv4 & IPv6

Floppy & DMA Controller

No floppy support


UART (COM Ports)

Optional UART for debugging

Faster and more reliable

i8042 keyboard controller

Software based input

No emulation – reduced resources

PS/2 keyboard

Software based keyboard

No emulation – reduced resources

PS/2 mouse

Software based mouse

No emulation – reduced resources

S3 video

Software based video

No emulation – reduced resources




Programmable Interrupt Controller (PIC)

No longer required


Programmable Interrupt Timer (PIT)

No longer required


Super I/O device

No longer required


There is much more to the new capabilities in the associated Windows Server 2012 R2 Hyper-V, but I need to keep my test environment at Hyper-V 2012 for a little bit longer due to some demo requirements, but then I’ll be able to post a bit more.