zhcon supports three different video drivers: framebuffer
(fast), VGA (slow), libggi (slow). On start up zhcon will
try to select best driver to use. If the framebuffer device
is not available (not compiled into kernel) it will fall back
to use VGA driver that works under 640x480x16 color mode,
which is quite slow.
To achieve best performance, it is recommended to always
use framebuffer driver in (8bit) 256 color mode. Speed will
no longer be a problem.