As a computer field tech, I use the remote desktop program UltraVNC quite often. I utilize it mostly to connect to offsite computers so I can run diagnostics and repair remotely, if needed.
Recently, I ran into an issue with UltraVNC and Vista. I was able to connect but the desktop was slow to the point of being almost non-responsive. There was no way I would be able to diagnose let alone repair anything over that connection.
After adjusting various color depth and screen resolution options without any noticeable improvement in speed, it dawned on me that I was connected to an Aero enabled Windows Vista machine. Sure enough , when I disabled Aero, the remote desktop sprang back to life.Here’s how disable all Aero features for UltraVNC sessions.
Disable Visual Effects
Right click on Computer, and choose Properties.
Click on Advanced System Settings, and then under Advanced, click Settings.
Select the "Visual Effects" tab, and then click “Adjust for best performance” and OK.
I've found that this dramatically speeds up the remote connection. Note that you should probably re-enable the old setting
after you are done.