Mac Forum / General / General / July 2006

There's only one external video socket, so you're out of luck.

However... anyone tried one of these? They come with Windows drivers
but I wouldn't be entirely surprised to see that they work driverless
anyway: http://shopmatrox.com/europe/products/datasheet.asp?ID=306

    Cheers - Jaimie

Probably not, but like to know if anyone can prove me wrong.

Consider the MacBook first.

The DVI connector doesn't support multiple displays.

The only other external connectors which theoretically allow a display
to be connected would be USB 2 (480 Mbps, but much less in reality),
Firewire (400 Mbps, probably able to almost achieve that) or Gigabit
Ethernet (1000 Mbps, might be able to get close to that).

To support a bare minimum VGA display (640x480 at 60 Hz with 256
colours) requires a data rate of about 147.5 Mbps, assuming no data
compression. A more reasonable "thousands of colours" would be double
that (295 Mbps), which is close to the achievable limit of USB 2
assuming no other devices are sharing the bus.

This all assumes that someone has actually made a display device which
can be connected to one of these ports, and Mac drivers to support it.
It would have to reserve a chunk of real RAM as a display buffer.

With a MacBook Pro, there is also the option of using the ExpressCard/34
slot. This could probably support higher data rates, but I don't know
whether it technically feasible to make a very small video card which
would fit in this slot (with its own video RAM and attendant heat
issues). Perhaps one which used main RAM as its video buffer and just
had the output circuitry on the card.

With both machines, it may be possible to get a limited display output
via the Firewire port, as you can send DV to a video output device, from
where it could go to a screen. This probably can't be used as a general
purpose display (expanding the desktop for use by any application)
because DV is compressed and the resulting video would only be viewable
on something resembling a standard or high definition TV, with limited
resolution and image quality. It might be feasible for special
applications (e.g. a dedicated application displaying video on a special
monitor while using the internal screen and one other external monitor
for the desktop display).

How do you want to hook them up?  Do you want a desktop extended over
three or more monitors, or do you want the single monitor desktop
repeated on three or more monitors?  The first, probably not; the
second, possibly.

mailpitches@email.com schrieb:

Macbook no. Macbook Pro yes, if you can find a video card for the
ExpressCard slot. VillageTronic has such a PC Card, but not yet an
ExpressCard, but I am sure they are working on it.

Stefan