Citrix described virtual desktop infrastructure (VDI) performance differences using various hypervisors.

Citrix has done some testing with different Hypervisors to see which hypervisor used makes a difference with desktop virtualization. These tests were conducted internally, by Citrix virtualization team.
Only Citrix XenDesktop 4, desktop virtualization solution was used for the tests. VMware’s View desktop virtualization application was not tested. The test results were described by Simon Crosby, chief technology officer for Citrix Data Center and Cloud Division, in a blog post here.

Performance was measured based on virtual machine (VM) density on a single server, running Windows XP or Windows 7 as guests. The hypervisors tested included Microsoft Hyper-V R2, Citrix XenServer 5.5 and an undefined “other” hypervisor group( so you probably guessed which one already).
For the Windows 7 guest(virtual desktops), Microsoft’s Hyper-V R2 hypervisor supported the highest VM density. While, Citrix XenServer 5.5 hypervisor scored the highest VM density when running the Windows XP guest.

Simon Crosby noted that the performance differences on Hyper-V R2 between the two Windows guests. “For Windows XP guests Hyper-V R2 doesn’t do such a fabulous job,” Crosby wrote in the blog post. Crosby continued: “I’ve spoken to Jeff Woolsey, PM for Hyper-V, who acknowledges this readily because XP has a relatively short remaining lifetime, and because of the focus at Microsoft on Windows Server workloads and Windows 7 as the new client OS.”

According to Citrix, they plan to test the most current hypervisor products — including Hyper-V Service Pack 1 and XenServer “Midnight Ride” — and “publish the results soon,” according to Crosby. Midnight Ride is the next version of XenServer and is currently available as a beta release. They new XenServer “Midnight Ride” features more options to enhance performance when it comes to running Windows 7. Here are the new features in Xenserver “Midnight Ride:

• Granular Role-based Access Controls. Administrative users can be assigned one of several roles, which govern the actions they are able to complete from XenCenter and the command-line interface (CLI).
• Administrative Logging and Audit. Administrative changes made from XenCenter or the CLI are logged and available in the Workload Reports in XenCenter.
• Dynamic Memory Control. This feature can increase the density of virtual machines running on a host by reducing the memory footprint of existing virtual machines so that new ones can boot.
• Enhanced VM Snapshots. It is now possible to create full VM snapshots including the disk and memory state.  Virtual machines can be easily rolled back to prior snapshot states with a “revert to snapshot” option.
• Automated Workload Balancing & Power Management. Workload balancing (WLB) recommendations can be applied automatically without administrative intervention.  Power Management features include support for wake-on-LAN and vendor-specific implementations from HP, Dell, and others.
• StorageLink Site Recovery. Enhanced integration with storage-level replication enables recovery of an entire virtual infrastructure at a secondary disaster recovery site.
• Citrix License Server integration. Essentials for XenServer features are now activated using a license applied to a Citrix Licensing Server. 
  

To Download and test XenServer 5.6 click here

Also Microsoft announced a upcoming service pack for Windows Server 2008 R2. This service pack will have new features like dynamic memory management capability, which will allow the memory use of VMs to be adjusted on demand. The new version will also include RemoteFX desktop virtualization technology in collaboration with Citrix. RemoteFX designed to improve the graphics experience for remote Windows users, and it will be interesting to see what performance will come out of that. While Citrix has their HDX Technology which works brilliant. To see more of what Citrix HDX has to offer click here

Parts of this article are gathered both from the blog post by Simon Crosby and from Redmond Mag