Re: Does the video card play any role in RDP/Citrix sessions?
- From: "Cláudio Rodrigues" <Claudio.Rodrigues@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Mon, 11 Sep 2006 20:14:50 -0400
Thinanywhere has been selling this technology for years, to accelerate
OpenGL apps on Citrix or plain TS (ICA/RDP).
Pricey but really worth if you do need that kind of functionality.
--
Cláudio Rodrigues
Microsoft MVP
Windows Server - Terminal Services
"Bernhard Tritsch [MVP]" <bt@xxxxxxxxxxxxx> wrote in message
news:Os6Y$GC1GHA.4016@xxxxxxxxxxxxxxxxxxxxxxx
Terminal Services both on Windows Server 2003 and Windows XP include a
driver that acts as the video driver within the TS user sessions. This
means that the local video hardware on the server is not used. All
graphical output created inside the TS user sessions is directed through
the RDP video driver, which converts the GDI calls into an RDP video
stream being forwarded to the network driver. As a result the quality of
video hardware on the Win2003-based or XP-based Terminal Server does not
directly affect graphics performance of TS user sessions. This is why the
video driver of Virtual Server that is being used by Windows XP as a guest
system will not directly affect graphics performance of the remote
connections via RDP. Performance will only be degraded by multiple
instances of Windows XP running in their VMs when they all try to access
the resources on your host server--such as RAM and CPU.
Things look differently on the client side. Here good graphics hardware
can make quite some difference compared to poor performing video cards.
Again the reason is obvious: The RDP data stream reaches the network
protocol stack on the client. It's forwarded to the RDP client
application, which converts the included video information into graphics
commands displayed by the local video driver + video card. Fast video card
in conjunction with enough CPU power (used for RDP decompression and
decryption) on the client side means better graphics performance.
As you can imagine, graphics performance is also affected by the network
bandwidth available for the RDP data stream. A high-end server on one side
and superior graphics hardware on the other side of the network won't help
you if the transport of RDP video data sucks.
BUT there is a big problem regarding AutoCAD. I think AutoCAD uses OpenGL
or some other 3D graphics standard, which is accelerated by good local
graphics hardware. This hardware acceleration will not work using RDP. If
you run AutoCAD in a TS environment, the OpenGL graphics will be converted
into pixels on the server side only using the capabilities of the RDP
driver. Those pixels will be transmitted to the client within the RDP data
stream and displayed on the client side. As you can imagine, this is not
the most effective way.
For AutoCAD users, in your Virtual Server scenario you are making things
even worse: You are running Windows XP within Virtual Server, the system
driver settings are not optimized for high-end graphics. Additionally you
the RDP protocol stack described sooner, which is not optimized for
high-end graphics applications as well. I doubt that AutoCAD will run
smoothly in such an environment. For all the other standard applications,
however, your scenario looks good.
Currently Citrix is working on Project Ocelot, which will be able to take
advantage of OpenGL graphics accelerators in SBC scenarios. This may
change the landscape of using high-end graphics in TS environments. But
today, your users will not be very happy with the performance of their
AutoCAD if they were used to running it on their local high-end
workstations.
Benny
--
Bernhard Tritsch
MVP Windows Server - Terminal Server
Author of "Windows Server 2003 Terminal Services", MS Press
http://www.wtstek.com
---
<doug.masters@xxxxxxxxx> wrote in message
news:1157809577.621251.215250@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I'm inclined to say "not really" but that's based on nothing, just a
hunch.
To make a long story shorter.... We're looking at buying a very well
equipped Dell 9-series server to run 7 virtual XP Pro systems via MS
Virtual Server. Server & Virtual Server will be the 64-bit edition,
the XP's guests will be 32-bit and the users will access the XP guests
via RDC. The XP boxes will be running a few minor in-house developed
apps, nothing exciting or demanding really except.....they will also be
running AutoCAD 2006 on occasion.
The boss is concerned that the lack of video power on the server will
cause issues with the XP systems, but I say that it all looks like host
processor use since the XP systems aren't real.
Anyone able to shed any light on this?
.
- References:
- Does the video card play any role in RDP/Citrix sessions?
- From: doug . masters
- Re: Does the video card play any role in RDP/Citrix sessions?
- From: Bernhard Tritsch [MVP]
- Does the video card play any role in RDP/Citrix sessions?
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