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Cable quality is IMPORTANT! Use only high-quality USB 2.0 compliant (not compatible)
cables. We recommend a minimum size of 24 awg (power) and 28 awg (signal). Cheap cables
can cause excessive voltage drops that can lead to system stability issues.
The maximum length of a USB 2.0 compliant cable is 5 meters. A hub or repeater can be used to
extend the cable to 10 or even 15 meters, but each hub (the U170 is a hub) or repeater counts as a
hop and you can’t exceed 5 hops on a port.
CPU Performance:
It is easy to check CPU utilization by using the Windows Task Manager in Windows. It gives
clear and constant feedback on the percentage of processing power consumed making it easy to
evaluate your environment to determine if the amount of processing power needed for a given set
of applications is available. For the majority of productivity applications and many multi-media
applications, most dual core processors provide more than enough performance to handle 6 or
even 10 users at one time*.
NComputing recommends you test your actual application set
prior to wider deployments
.
NComputing’s operating system testing with our vSpace software has demonstrated excellent
“fair share” processor utilization that enables all tasks to be serviced equally. This means that
even if the CPU usage spikes to 100%, vSpace and the operating system evenly distribute the
available CPU capacity across all the stations. So in the cases where the CPU hits 100%, each
individual station’s performance slows on a sliding scale. For example, a user’s perceived
performance may move from 2.5 GHz to 2.0 GHz to 1.5 GHz and then spring back once the
demanding task is completed. Additionally, those times when the actual processing requests
exceed what was anticipated are usually very brief, and user performance normally returns to
near the host PC’s native speed very quickly.
* Generally the most stressful CPU test for a U170 is video decoding at full screen. Playing a
video stream is highly dependent upon the video file type; then somewhat on the video player
(decoder) and screen resolution. We benchmark against D1 (or DVD) sized videos of up to a
NTSC Wide-screen resolution of 720x480. Again most current P5 class Intel/AMD dual core
processors can handle many streams, at once, if more are needed simply upgrade the processor.
Memory:
The second PC resource to check is memory utilization and it can easily be checked via the same
performance tab within the Windows Task Manager. NComputing generally recommends
provisioning the host PC with 2-4 GBytes of memory.
Also check your paged memory usage to be sure it doesn’t exceed the OS limits of 372 MB (XP)
or 530 MB (Server 2003) (marked in red in the Task Manager below).
