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What you need to know about Microsoft RemoteFX

Microsoft's RemoteFX desktop protocol delivers "perfect" Windows 7 virtual desktops, as long as the conditions are exactly right.

The wait is over! After years of talk and previews and betas, Microsoft finally released its RemoteFX enhancements for RDP. The new feature delivers the "perfect" Windows 7 virtual desktop experience -- as long as you meet Microsoft's explicit prerequisites.

Microsoft promises that the RemoteFX add-ons to Remote Desktop Protocol (RDP) create a high-quality user experience for Windows 7 desktops running in a virtual desktop infrastructure (VDI). We're talking multiple displays, 1900x1200 resolution, full Aero Glass, multimedia, 3-D, USB -- everything! Connecting to a remote Windows 7 desktop via RemoteFX can provide a user experience that's indistinguishable from a locally running copy of Windows 7.

Sounds great, right? Unfortunately, there is some major fine print to read if you want this awesome new perfect Windows 7 RemoteFX experience.

First, RemoteFX is available only if you're connecting to a Windows 7 Service Pack 1 remote virtual desktop. So for everyone who's still using Windows XP as your remote host, no RemoteFX for you!

Second, RemoteFX works only when a Windows 7 SP1 virtual desktop is running on Microsoft Hyper-V 2008 R2 SP1. If you're using VMware vSphere or Citrix XenServer, no RemoteFX for you! This also means that you can't use RemoteFX to connect to remote physical Windows 7 hosts, like high-end workstations or server blades. Your remote desktop must be running as a virtual machine (VM) on Windows Server 2008 R2 SP1.

Third, RemoteFX does some very heavy-duty encoding on the remote host side to process all of the intense graphics. Your remote server must have a powerful graphics processing unit (GPU). In other words, you need to install a gamer's graphics card in your server. (I hope it has room!) What's interesting is that Microsoft doesn't use the GPU for screen graphics processing in the normal way. Instead, extensions to Hyper-V in 2008 R2 SP1 allow RemoteFX to leverage the GPUs enormous floating-point computational ability to handle the encoding of the graphics screens.

In addition to needing to buy a graphics card for your remote desktop server, you need a lot of graphics card memory for each RemoteFX-based remote screen running on that server. (A single 1900x1200 screen requires 220 MB of memory.) Multiply that by the number of screens and users you have, and you can see that a typical 4 GB graphics card runs out of memory really fast. If you want to support more users than that, then you need to add more graphics cards. This can be a challenge, because how many of your rack-mounted servers have room for a bunch of power-hungry, double-wide, custom-fan graphics cards? Oh, and not to mention, these things are freaking expensive!

Finally, RemoteFX is a LAN-only solution at this time. That's easy to understand, since it takes a lot of bandwidth to pump those "perfect" screens down to users. Microsoft claims that it might support WAN and Internet scenarios in the future, but for now, it's LAN or nothing. (If you're feeling bold and want to try WAN-based RemoteFX, check out WAN acceleration products from Riverbed Technology and Quest Software.)

So, Windows 7 only, Windows running in a VM only, Hyper-V only, LAN only, and expensive, large, power-hungry graphics cards. Does RemoteFX sound like something you want to use today? Suddenly, Citrix HDX and VMware PC-over-IP are looking pretty good.

One final note: Microsoft also supports RemoteFX for Remote Desktop Session Hosts (the stupid new name for Terminal Services), but the way it's used there is very different, and you don't get the same "perfect" experience that's possible with RemoteFX for Windows 7 VDI scenarios.

Later this week, I'll write a follow-up article that explores RemoteFX on Terminal Server.

Brian Madden
is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog,, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.

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