Remote Desktop Protocol Performance Improvements in Windows Server 2008 R2 and Windows 7

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MICROSOFT

Remote Desktop Protocol Performance Improvementsin Windows Server 2008 R2 and Windows 7Microsoft Corporation January 2010

CopyrightThis document is provided as-is. Information and views expressed in this document, including URL and other Internet Web site references, may change without notice. You bear the risk of using it. This document does not provide you with any legal rights to any intellectual property in any Microsoft product. You may copy and use this document for your internal, reference purposes. This document is confidential and proprietary to Microsoft. It is disclosed and can be used only pursuant to a non-disclosure agreement. 2010 Microsoft. All rights reserved. Microsoft, Aero, ClearType, Internet Explorer, PowerPoint, Silverlight, Windows, Windows Media, Windows Server, and Windows Vista are trademarks of the Microsoft group of companies. All other trademarks are property of their respective owners.

ContentsCopyright.................................................................................................................... 2 Contents..................................................................................................................... 3 Overview .................................................................................................................... 4 User Scenarios............................................................................................................ 5 Test Setup................................................................................................................... 6 Remote Desktop Connection Settings......................................................................6 Presentation Virtualization..........................................................................................9 Color Depth.............................................................................................................. 9 ClearType Virtualization (a.k.a. Font Smoothing)....................................................11 Desktop Composition.............................................................................................13 Embedded Multi-Media Performance......................................................................14 Multi-Media Redirection..........................................................................................16 Effects of Latency on Broadband Remoting Performance.......................................17 Conclusion................................................................................................................. 18 Appendices............................................................................................................... 19

OverviewWith the release of the Windows Server2008 R2 and Windows7 operating systems, Remote Desktop Protocol (RDP) is more feature rich, enabling new presentation and remote-oriented functionality such as accelerated bitmap rendering, multi-media redirection streaming, and network topology awareness. In short, RDP is better able to support todays ever increasingly complex and rich multi-media environment. As these features become integrated in the enterprise environment, it is important to analyze and understand their impact on your current network infrastructure and the end-user experience. This paper details different RDP features and the potential improvements to usability and quality of the end user remoting experience as well as system deployment metrics. It also includes performance considerations for individual features that can help guide your decisions when modifying your deployment configuration to improve performance or tune it to the specific needs of your end users. To test the impact of different features and compare RDP 7.0 to the previous RDP 6.1 version, we performed a variety of tests by using automated and simulation tools to demonstrate the user scenarios outlined in this white paper. These tests are broken down into two broad groups: a set that simulated a user working with actual Microsoft Office applications at realistic speeds, and a set of multi-media scenarios that simulated a rich media environment commonly expected by todays and tomorrows users. In addition, some of the scenarios have been run at increased network latencies to demonstrate the viability of using RDP in distributed environments, such as in Branch offices or telecommuting scenarios where broadband capabilities exist. Comparisons of previous versions of RDP are covered in previous white papers. However, their results cannot be directly compared to the results presented in this white paper because the test server/client hardware as well as networking, the scenarios, and Office applications have all been updated to reflect current industry expectations. For example, the display sizes used have been updated to reflect higher desktop resolutions.

User ScenariosFive different user scenarios were used to measure the performance of the Remote Desktop Connection (RDC) client. Executive/Complex PowerPoint Scenario. This scenario emulates a user presenting 43 high-fidelity slides by using Microsoft Office PowerPoint 2007. The slides contain images, transitions, and backgrounds with color gradient. The user spends a minimum of 20 seconds viewing each slide. Simple PowerPoint Scenario. This scenario emulates a user presenting content by using PowerPoint 2007. The slides in this scenario are more textintensive than those in the executive PowerPoint scenario and have plainer backgrounds and simpler images in the form of black diagrams. Typing and Scrolling Scenario. This scenario emulates a user that is using Microsoft Office Word 2007. First the user opens a document and resizes its window and then highlights and changes the font (to Arial 10 point). Then the user opens a 17-page document (the RDP 5.1 compared to RDP 6.0 comparison white paper) and then resizes this document two times before starting to scroll through this document at around 2 pages per minute (at a minimum of 800 milliseconds per line of text). After completing the scrolling, a new document is opened and 1068 lines of text consisting of 7059 words is typed into it at a maximum rate of four characters per second, which equates to an average user typing at 35 words per minute. Internet Explorer Scenario. This scenario emulates a user browsing the Web by using Windows Internet Explorer 8. The user browses and scrolls through multiple Web pages that contain a mix of text, natural images, and some schematic diagrams. The rate of scrolling is one line every 200 milliseconds, and this Web page takes around ten minutes to scroll through. The Web pages are stored on the local disk drive of the Remote Desktop Session Host (RD Session Host) server to avoid errors due to varying load times. Multi-Media Sample 1. This scenario contains a short variable bit-rate Adobe Flash-encoded video embedded in a Web page that is stored on the local hard drive of the RD Session Host server. The video is played within Internet Explorer 8 by an embedded player plug-in. This scenario emulates users viewing rich content Web pages containing multi-media. The resolution of the Adobe Flash video is 1152 by 688 pixels. Multi-Media Sample 2. This scenario contains a short fixed bit-rate Silverlight-encoded video embedded in a Web page that is stored on the local hard drive of the RD Session Host server. The video is played within Internet

Explorer 8 by an embedded player plug-in. This scenario emulates users viewing rich content Web pages containing multi-media. The resolution of the Silverlight video is 1024 by 576 pixels, its total data rate is 5000 kilobits per second (Kbps), and it renders at 29 frames per second (fps) with 64 Kbps mono auto. Multi-Media Sample 3. This scenario contains a thirty-second Windows Media (WMV)-encoded video at 29 frames per second at a resolution of 1280 by 720 pixels with a 192 Kbps audio track. This scenario is used to test multimedia redirection.

Test SetupThe tests were conducted in a private lab to avoid external network interference. The results in this white paper are the average of three to five test runs depending on the standard deviation between the individual runs. Details of the server and client systems used can be found in the Appendices together with additional details of how certain measurements were taken, and how they should be interpreted.

Remote Desktop Connection SettingsTests were run by using the following range of Remote Desktop Connection client settings. As the RDP 6.1 client and RDP 7.0 client vary in their interfaces slightly, both are fully detailed. All test results indicate the setting combinations used for testing when a one-to-one direct mapping did not exist. Color depth: High Color (16-bit) and Highest Quality (32-bit) Connection speed setting on the Experience tab: a. Windows Vista with Service Pack 1 client Default: Modem - 56 kilobits per second (Kbps) LAN: 10 megabits per second (Mbps) or higher

b. Windows 7 client: Default: Low-speed broadband - 256 Kbps to 2 Mbps LAN: 10 Mbps or higher WAN: 10 Mbps or higher with high latency

Default bulk compression and persistent bitmap caching settings Font smoothing (ClearType): On or Off

Desktop composition (AeroGlass): On or Off

Chart 1 shows all the different client configuration options used in this report and their default settings.RDP versi onClient connecti on setting Desktop backgrou nd Font smoothi ng Desktop composit ion Show conten ts while draggi ng Menu and window animati on Visual styles/the mes Persisten t bitmap caching

6.1

Defaul tModem 56 Kbps

6.1 7.0

LAN Defaul tLowspeed broadban d

7.0 7.0

LAN WAN

Chart 1: Client configuration options used in this report and their default settings

Presentation VirtualizationColor DepthIn previous versions of RDP, 16-bit color depth always reduced the networking resource requirements of deployment compared to the 32-bit color depth introduced with Windows Vista in RDP 6.1. In Windows Server 2008 R2, RDP 7.0 utilizes an improved bitmap compressor so that, for the first time, the higher fidelity of 32-bit color is obtainable at lower bit rates than 16-bit color for many common scenarios. Note: The 8-bit color depth is no longer supported in Windows Server 2008 R2 for Remote Desktop Services. True Color (24-bit) support was retired in Terminal Services in Windows Server 2008. The only valid options for Windows Server 2008 R2 are High Color (16-bit) and Highest Quality (32-bit). Table 1 and Chart 2 compare the total bandwidth (in bytes) consumed by a user scenario that uses different color-depth settings. The tests were conducted by using the default connection settings (56-Kbps modem connection setting in RDP 6.1 and the low-speed broadband setting in Windows 7) with the default bulk compression settings.

Scenario Complex PowerPoint Simple PowerPoint Word Scroll and Type Internet Explorer 8 Scrolling

RDP 6.1 16 bpp 8750710 2 4268043 1 2245601 4017795

RDP 6.1 32 bpp 8769843 7 4260099 2

RDP 7.0 16 bpp 7345618 2 3617212 1 2846335 4356808

RDP 7.0 32 bpp 6566194 3 3287343 8 6782496 1099161 0

957986 21543690 9

Table 1: Color depth comparison for different knowledge worker scenarios

Scenario Complex PowerPoint Simple PowerPoint Word Scroll and Type

RDP 6.1 to RDP 7.0 16 bpp -16% -15% 27%

RDP 6.1 to RDP 7.0 32 bpp -25% -23% -29%

Internet Explorer 8 Scrolling

8%

-29%

Table 2: Network traffic of RDP 7.0 compared to RDP 6.1 by scenario and color bit depth. Less is better.

Chart 2: Color depth comparison for different scenarios

Chart 3: Network traffic of RDP 7.0 compared to RDP 6.1 by scenario and color bit depth. Less is better.

Tables 1 & 2 and Charts 2 & 3 show that RDP 7.0 is more efficient at remoting bitmap-rich content by reducing between 15% to 29% the total network traffic generated for 32-bit color depth displays. 16-bit color depth is less effective with reduction in bandwidth for PowerPoint, Web browsing, and Word scrolling and typing.

ClearType Virtualization (a.k.a. Font Smoothing)ClearType display technology is a Microsoft font smoothing technique that improves the readability of text on LCD screens. With the proliferation of LCD screens and the release of WindowsVista, Windows 7, and Office 2007, ClearType has become very important. Most of the fonts available in WindowsVista and Office 2007 are tuned for ClearType and look unattractive when it is turned off. Due to these reasons, Remote Desktop Services decided to give the user the option to turn on ClearType. You can get ClearType in the Remote Desktop Connection (RDC) 7.0 client by going to the Experience tab and selecting Font smoothing. However, the high fidelity of ClearType comes at a cost. Normally (with Font smoothing disabled) fonts are transmitted as glyphs. Remote Desktop Protocol transmits glyphs efficiently and caches them to reduce bandwidth

consumption. With ClearType enabled, fonts are transmitted as bitmaps and not as glyphs; transmitting these bitmaps to the client results in increased bandwidth consumption. From our initial internal testing, we found that enabling ClearType for text scrolling and typing scenarios resulted in an increase in bandwidth consumption that was 79% to 83% greater than when the scenario was run with ClearType disabled (in contrast to RDP 6.1 where enabling ClearType cost between 1x and 2x of extra bandwidth). In RDP 7.0, ClearType can be enabled in many instances without significant impact in bandwidth compared to RDP 6.1. Table 3 and Chart 4 show the total bandwidth consumption (in Bytes) for user scenarios running at 16-and 32-bit color depths with the LAN connection setting + ClearType or Font smoothing explicitly turned off or on.RDP version RDP 6.1 - 16bpp RDP 6.1 - 32bpp RDP 7.0 - 16bpp RDP 7.0 - 32bpp Font smoothing enabled 5039496 30295938 5465492 12371554 Font smoothing disabled 2441593 9579862 3059905 6771320 Bandwidth increase using font smoothing 106% 216% 79% 83%

Table 3: Total bandwidth consumption for ClearType text versus Normal text

Chart 4: Bandwidth consumption for Font smoothing On and Off

Font smoothing is disabled by default on the RDC client, and can be enabled on the Experience tab either explicitly by selecting the Font smoothing check box or by setting a faster connection type setting such as LAN or WAN. The RemoteApp Wizard enables font smoothing by default. In Windows Server2008 R2, to provide a mechanism to control this setting for all RDP 7.0 remote clients, you can apply a Group Policy setting to disable font smoothing.

Desktop CompositionThe Desktop composition feature fundamentally changes the way applications display pixels on the screen. When Desktop composition is enabled, individual windows no longer draw directly to the screen or primary display device as they did in earlier versions of Windows....

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