Quote Originally Posted by SourceChild View Post
I have done plenty (too many) shows with dual TH2G. They have all been on 2008 machines with 8800s. Just because I have done this does not mean I suggest this. In fact, I won't do it anymore.

In the 2009 or 2010 machines, I have not been successful in using 2 TH2G boxes, especially mixing 2 different types.

The best recommended configuration for a TH2G is to place it on the second Output and have a monitor or 4th out on the First Output.

I will also note that 1280x1024 is 5:4 ratio not 4:3. If your output devices are 5:4 then using the 1280x1024 is reasonable. Otherwise, stick with 1024x768 unless you absolutely need the resolution. Then only use a 5:4 if your projectors are 5:4 otherwise, you'll need to use the Matrox Desktop to enable 1280x960 which is 4:3.
i think there is a maximum limit which the graphics card will do
and
i think there are some things with display port bandwidth and how this works - how many output lanes are in use

there has possibly been some architecture change to recent graphics cards which puts a lower limit on output sizes

http://en.wikipedia.org/wiki/DisplayPort
http://en.wikipedia.org/wiki/Mini_DisplayPort

http://store.apple.com/us/product/MB571Z/A

DisplayPort is capable of directly emitting single-link HDMI and DVI signals using Dual-mode DisplayPort. VESA has issued interoperability guidelines for supporting single-link DVI and HDMI through a DisplayPort connection using a relatively simple passive adapter that adjusts for the lower voltages required by DisplayPort.[15][16] Dual-mode DisplayPort chipset detects the DVI or HDMI passive adapter and switches to DVI/HDMI mode which uses the 4-lane main DisplayPort link and AUX channel link to transmit 3 TMDS signals plus a Clock signal and Display Data Channel data/clock from the chipset. Dual-mode compatible ports are marked with the DP++ logo; most current DisplayPort graphics cards and monitors support this mode.[4]
A notable limitation is that dual-mode can only transmit single-link DVI/HDMI, as the number of pins in the DisplayPort connector is insufficient for dual-link connections and an active converter is needed for Dual-Link DVI (and analog component video such as VGA); however, VESA foresees that all HDMI conversion will eventually be handled by active adapters which act as DisplayPort Sink devices, in order to facilitate easier updates to latest HDMI specs and support multiple streams, dual-link HDMI,[4] or DisplayPort connection with fewer than 4 lanes, as in PDMI. DVI 1.0 spec was finalized in 1999 and the DVI industry consortium has since disbanded, which means future updates to DVI specification are unlikely; also, although dual-link HDMI Type B is defined in the HDMI specification, it has not seen any practical use so far