[SunRay-Users] Sun Desktop Access Client (SDAC / soft client) poor performance

Devin Nate Devin.Nate at cloudwerxdata.com
Mon Mar 1 19:14:49 EET 2010

Dear SunRay Users;

We have begun testing the Sun Desktop Access Client (SDAC), and have experienced poor performance. I am looking for a solution.

When I say 'poor performance', we are seeing laggy screen redraws and 'blocking' where certain blocks of the screen will be visibly not updated. We run nearly exclusively in kiosk mode, using uttsc, and the operations/things we're doing are very basic (we are not watching movies, flash, etc). All we are doing is logging in, opening word/excel, pushing the start button, etc., all which show lag and blocking. The performance is such that while technically working, the end user experience isn't solid enough that we can deploy the SDAC.

By comparison, on the exact same network and using the same Sun Ray Servers v5, we have a number of Sun Ray ultra thin clients (DTUs). The Sun Rays work as desired, and if the SDAC was working the same I'd be more than happy. I'm rather shocked that a full fledged PC cannot achieve the same performance.

Also by comparison, raw RDP from the PCs achieves the same excellent performance as the Sun Ray thin clients.


Our srs servers are 2x Red Hat Enterprise Linux 64-bit servers running the most current SRSS software. They live in VMware ESXi v4.0u1 Enterprise, and exist in a FOG configuration. The Sun Ray Servers are connected via internet to our clients ... so the actual DTUs are not on the same LAN as the Sun Ray Servers. There is an approx 15-25ms rtt for ping/icmp packets. Again, I don't suspect a server problem, in so much as the Sun Ray DTUs work excellent.

Our DTUs are Sun Ray ultra thin clients, model 2's and model 270's. They work great. They are connected to the exact same network/ports/etc as the PCs below. These DTU's have a MTU of 1200.

PCs using SDAC:
Our PCs are a combo of Windows 7 professional 64 bit and WinXP professional 32 bit. All running SDAC 1.0.51. These are the machines that see the performance/blocking problems. We've adjusted MTU in the software ranging from 500 (the minimum) to 1500 (the maximum), including at 1200. We've also turned on/off compression and lossless compression. None of these options have helped.

Thanks, and look forward to any information people can share that might help.
Devin Nate

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