I have upgraded today to gnome 2.2 now when I scroll though a medium sized file, a squid.conf or XF86config for example the system struggles to keep up and displays noticable slowdown, this is confirmed by showing a very high load on the system when scrolling local or remote files. as far as im aware the biggest change in gnome-terminal included with gnome 2.2 is that it now links against libvte.
I have tested this with and without transparecny settings and can confirm the problem is aparent in both states. When calling konsole ( from within gnome ) the problem is not apparent.
well there is your problem, it uses pango and it is slower. disabling the transparancy might help as well. Not much we can do about it, just keep up to date with the latest vte/gnome-terminal releases and it will improve (it has improved a lot over the time i've used it). zvt is not supported anymore.