100% CPU load

[Solar]

Using various operating systems and machines, I often have the problem that the VNC server eats up all of the available CPU.

The 100% CPU load problem only occurs, if I have my mouse inside the viewer's window.
If I'm logged in but keep my mouse out of the remote desktop, usage is like it should be.
But whenever I have the mouse inside, 100% or how much there's left gets used.

If I view only, inputs ignored, there is no problem.

I can't really say what's the problem, using same hardware/software, sometimes
it works just fine, and sometimes it uses up everything left and slows down other processes.
It's no difference if I use UltraVNC or TightVNC, you never know..

For example, this time I re-installed Windows 98 on an old PC.
Before, VNC server always used up the CPU resources.
But this time, it worked just fine using Ultra's WinVNC Server 1.0.2

The most mystical thing, some days later, it again eats up resources!
Same server, same client, same system/drivers, I think same settings as didn't change them, but it eats up :(

It must have something to do with how mouse movement is sent to the server.
Now that there's load, the remote cursor is instantly under my local mouse, also if I move only some px,
sometimes flickering for a very short moment somewhere around, but then being exactly where my local mouse is.
If I remember right, this was somehow more relaxed, when it didn't eat up some days ago.
I don't need the movement with high precision, mainly only the final clicks :)

I had this problem also using Windows NT4, and I never understand why?
Sometimes just fine (12% or something), but at other times always 97% or so...

Another weird thing I just found out: Desktop, Explorer, Apps - all let VNC eat up 100%
But if I click the Win98 start menu, I can leave the mouse inside the viewer's window,
I can even move around, it wouldn't eat up resources. :?

Remember, using the same PC some days ago, without changing anything,
it did not use up the resources also when using Explorer, Desktop, Apps...

Any help is highly appreciated, because I really don't have any clue...

[moonmoon]

Sorry for the double post, does anybody have any clue.

[Solar]

Today it's just perfect, I didn't change anything.

The mouse cursor now isn't flickering, if I move, it will just follow up, relaxed so it's not immediately where I am, often for one moment on the way that I did. In contrast to the flickering that also occurs if I move only some px, where the mouse would flash in all directions for very short time. Where you have the feeling the cursor would move 1px in all directions and back like hell, or something.

CPU consumption is about nothing, also if I have it inside the window. Really nice at the moment