Turn off all polling. VB apps don't need it AFAIK.
On 15 Nov 2001 09:15:35 -0500, W. Brian Blevins wrote:
> Rick,
>
> As mentioned by others, disabling polling can reduce CPU usage on the
> server
> (host) system significantly. That is certainly the first thing to check.
>
> However, CPU time is also used to encode the updates. For fast networks,
> like 100MB/s, hextile has a low CPU utilization profile, but the raw
> encoding uses even less CPU time. Of course, it places higher demands
> on the network card and uses much more raw bandwidth. You can select the
> desired encoding in the vncviewer options dialog before connecting.
> In your environment, I would avoid zlib, zlibhex and tight, because they
> use more CPU time to generate less network traffic.
>
> Finally, WinVNC.exe must copy screen data from the video RAM back into
> main memory to detect changes. The speed of this operation probably
> depends
> on the video card and the video driver. Are these up-to-date?
>
> Further comments below.
>
>
> > Date: Wed, 14 Nov 2001 09:14:18 -0500
> > From: "Watson, Rick" <[EMAIL PROTECTED]>
> > Subject: VNC system resources useage on WIN2K
> >
> > We do public opinion surveys and use VNC to monitor the surveyor to make
> > sure their work is accurate. We had switched from M'soft SMS to VNC because
> > SMS was way too slow. We did that several years ago when our primary
> > application was DOS based. Now that we've upgraded to Windows software, VNC
> > has a serious impact on the speed of the interviewing software. I've tried
> > AT&T, Tridaic, and now TightVNC. It's not so much VNC, but the system
> > resources diverted to VNC on the client that causes the application to bog
> > down completely. The application uses Visual Basic. I'm sure the problem is
> > with machine resources and not network speed, we are on a 100MB line and
> > changing encoding/compression levels hasn't had a major impact. The machine
> > being viewed can have as much as 50% of their processor time used by VNC.
> > The clients are PII 450, with 128MB RAM.
> >
> > Does anyone have any ideas how to negate the impact on the client machine?
> > Is one version of VNC better at this than others?
>
> This is a matter of opinion of course, but I think you will make more
> progress in the area of CPU utilization by disabling polling and using raw
> or
> hextile that with switching VNC versions.
>
>
> > Also, for TightVNC is
> > there a way of using command switches to turn off CopyRect encoding and make
> > Display-View Only the default? It seems those have to be set each time.
>
> I think all versions of vncviewer.exe accept the "/viewonly" command line
> switch. Also, if you save the connection settings to a configuration
> file,
> you can use "/config file" to load those when starting the viewer.
>
> The latest source code for vncviewer.exe from www.developvnc.org supports
> a command line switch "/disableCopyRect". Currently the only way to get a
> *binary* for that from Tridia is to download TridiaVNC Pro:
>
> http://www.tridiavncpro.com/
>
> You didn't think I was going to end this email without a shameless plug
> for our product did you?
>
> >
> > TIA,
> >
> > Rick Watson
>
> --
> Brian
> ----------------------------------------------------------------------------
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