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We run Ultra VNC on our roomful of Windows 2003 servers.

On two servers, if you connect, and open Task manager>Performance, you see the CPU maxes out at like 98% (these are fairly new 4 core boxes)

If you disconnect and then connect back using Remote Desktop, the CPU usage is more normal.

We've wiped and reinstalled Windows on these boxes and it made no difference

Also, these boxes run line of business apps and operate normally in every other respect

We use Ultra VNC on several other dual and single core servers, with no problem and no excessive CPU use.

Has anybody seen anything like this?

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I've seen it -- happens on ONE of my win2k3 standard x64 boxes (sql server). Drives me nuts... it is also painfully (to the point of useless) slow with screen updates from vnc viewer. Watching this thread with interest. – Chris_K Oct 3 '09 at 1:03
Is Windows 32bit or 64bit? Our Windows Server 2003 servers are all 32bit installs and I've not seen this before. Also what version of UltraVNC? – user17642 Oct 3 '09 at 1:08
Why use VNC?--- – Izzy Oct 3 '09 at 1:39
The slow instances are 32 bit. VNC is a standard here and works very well - with 2 ecxeptions. One of the boxes I repaved has the very latest UltraVNC server and the other one has an older version – Anonymous Oct 3 '09 at 1:54
I'm w/ Izzy here. Why use VNC? I haven't used VNC heavily since W2K3 was released. (I still used it w/ W2K because there was no method to get a true "console" session like there is in W2K3.) – Evan Anderson Oct 3 '09 at 3:34

When looking at the two machines having problems, do they have the same video card? If so, is their video card different than others that are working fine -- or different drivers?

Do you have the mirror driver installed? If so, have you tried uninstalling it (or vice-versa)?

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+1 bump for the mirror driver, if it's not installed and working, then VNC is not working correctly. – Avery Payne Oct 6 '09 at 19:57
BTW, without the mirror driver, the behavior described is common - more CPU cycles are expended handling screen refreshes, but with the mirror driver, it cuts it by a factor of 10x. I've seen this on 2000, XP, and 2003, and it's a universal behavior. – Avery Payne Oct 6 '09 at 19:59

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