Improving screen redraw rate on thin-client over RDP to Server 2008 R2

Question

I've been reading about generally increasing the performance of an RDP session here but those posts don't seem to cover what I'm looking for which is specifically the redraw rate of windows. I'm not interested in video playback or CAD/graphical performance.

I have Wyse V10L and C10L clients connected to a Server 2008 R2 host. It's a virtual machine and it has enough horsepower to handle the client load. I don't believe the poor screen redraw rate has anything to with the host itself.

From my Win 7 machines using Remote Desktop Connection I get a fairly decent redraw rate that does not leave me feeling uncomfortable or annoyed. However, on the thin-clients the redraw rate is much lower and there's a big difference.

I've tried disabling compression, USB/serial/sound, and pretty graphics (font smoothing, backgrounds, window dragging, etc.). None of this has made even a small difference in the redraw rate.

Is it as simple as the Wyse hardware not being able to redraw any faster? I don't have a more powerful Wyse device to compare with. Any ideas?

Solution

Performance issues like you're describing are almost always (in my experience) network related. RDP sessions (in my opinion) are much more sensitive to network issues such as lateny, congestion, and packet loss than they are to almost any other resource issue (memory, CPU, etc).

That being said I've seen enough cases with dumb terminal performance to know that dumb terminals often don't have the horse power to provide a well performing session.

Your own test seems to bear that out; a full fledged computer running Windows 7 doesn't seem to be affected by the problem so that leads me to believe that the problem is with the dumb terminals themselves. If you have a newer, beefier terminal at your disposal I would drop that on the network and see how it performs. I would also try another workstation or laptop to see if you get the same good performance as the Windows 7 workstation. If a more powerful terminal or another workstation exhibit good performance than I think you can definitively point your finger at the terminals.

As a final note, there's only so much tweaking you can do on the server and/or the network before it becomes a "war of attrition" and leads to an excercise in futility. If the terminals are the problem then the resolution is to replace them. I went through this recently with a customer and the final resolution, after all the poking, prodding, and tweaking, was to replace the terminals.

Comments

[Zoredache]

What OS is the thin-client running? Does it have the proper video drivers? I know many linux-based thin-clients just use the a generic driver and performance sucks.

[Alo]

I would suspect the display adapters on the thin clients as well. Hopefully someone has a more powerful Wyse device that can confirm.

[Chris Gill]

These devices use the latest Wyse ThinOS.

[Chris Gill]

I'm pretty sure the client hardware is the issue at this point. I'm getting a demo of a different device from HP and I really don't know if it's more powerful or not so I'll just have to wait and see.

[Chris Gill]

I've uploaded an example of the redraw rate as seen from my Win 7 client. The new HP Windows CE 6 thin-client I just received today has the same poor redraw so I'm wondering if whether my experience is atypical or not. screencast.com/t/10wcha7V5BiK By the way this video was recorded on my Win 7 Ent desktop with 2GHz (quad core ) and 4GB of RAM.

[joeqwerty]

Any way to create a similar video from the dumb terminal session to compare it to the Windows 7 session?

[Chris Gill]

I had thought about that as well but except to use my cellphone I'm not sure. However, I can say that the redraw rate is almost identical. If you're able to make a comparison, how does an RDP session on your own workstation (and/or thin-clients) compare to the video I uploaded?

[joeqwerty]

The screencast is an example of the Win7 client, right? Because it looks pretty good to me. Are you saying that the terminal session is comparable to the Win7 session in the video?

[Chris Gill]

Yes, that's what I'm saying. For better or worse my goal, and my running orders, is to provide as good of a user experience as possible which is why I'm trying to get more fps.

[joeqwerty]

You can only do so much. A remote session is never going to quite compare to a local session. That screencast looks pretty good to me. There are a lot of areas you can look at tweaking but you might want to start with setting the session color depth to 16 bit and set the performance options on the server for "best performance".

[joeqwerty]

Glad to help...

[Chris Gill]

I posted this in 2011. :) We're no longer using the thin-clients as we migrated back to traditional PCs recently. The reason for that though was semi-unrelated to this post. We needed staff to start doing a lot more media consuming (watching videos) and that performance was abysmal. I tested several high-end Wyse devices and PCs alike (all using RDP) and the bottleneck was the CPU. We had two paths to take: invest in GPUs meant for virtualization or whitebox some PCs. We chose the latter and everyone (including us in IT) is happier.