Forums > Jitter

intel experience

December 1, 2006 | 10:05 pm

hi!

i have just made a strange experience working on an intel mini mac we
use for an installation.

i was planning to run the machine without a display connected as its
output is only sound and dmx with another part of the patch doing
jitter video processing of a live camera feed.

in such a situation i use a VNC server to be able to operate the
machine remotely.
this works flawlessly when an actual screen is connected to the mini
mac.
if i unplug the screen, though, and reboot without a display the
jitter performance drops from 30 fps to 5 fps.

now, if i do the same to a PPC mini mac the same thing happens, but
not quite as bad.
the frame rate drops from 11 fps to 7.5 fps, so that in the end the
PPC outruns the intel machine (!) which is actually 3 times as fast.

would anyone know a way to explain this?

as far as i understand it the intel machine does not have any
dedicated video ram anymore, but uses a part of the computers memory.
presumably the size of memory changes depending on the size of the
display and without an actual screen there, it could be very small.

could i fool the intel machine that there really is a nice 20 inch
screen there somewhere..?

any pointers would be appreciated!

many thanks
hiaz


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