Can I use one graphics card to run 5 monitors with a Mac

[ben2020]

Hi there!
I am doing a complex project which involves me projecting thirty 10 second video loops at a time using five projectors onto 5 screens.
To do this I am planning to use Resolume and a Mac Pro.
I spoke to the guys at Resolume and they said it was better to use one graphics card with 6 outs than 2 cards with 3 because Resolume is 32 bit not 64 bit and using 2 cards would put more of a strain on the program.
I need the videos not to stutter and because Resolume has the DXV codec which uses the graphics' card processor can anyone recommend a good graphics card with 6 outputs for a Mac?
Unfortunately I can't use a PC and it can be hard finding Mac drivers for many of the higher end cards.
All the video clips are 1024x576.
If anyone has any ideas I'd love to get your feedback.
Thanks a lot,
Ben

[MJ]

eh a ATI Radeon HD 5870 with 2 th2g's?

[subpixel]

You're talking about rendering 30 layers of almost HD video; seems unlikely to happen on a single machine.

You might find even 10 layers on one machine a difficult task. I have a Core i7 (quad core) non-Mac laptop with a 1GB ATI card and it can't handle much more than four 800x600 layers (mind you, those are XviD-encoded; I don't know how many DXV layers you can decode on a GPU).

Do you have 30 clips total, or some multiple of that? If you can't fit all the video in memory, you're going to need some serious storage solution with high bandwidth and low latency.

Perhaps fill in some details about how you intend to use the clips and so on.

You *might* get some benefit in cutting your frame size down to 1024x512, since it is possible that 1024x576 will end up occupying a 1024x1024 video texture (double the "cost").

-spxl

[subpixel]

Try looking at some numbers:

Let's say 30fps video

1 second is: 30 * 1024 (width) x 576 (height) * 3 (bytes per pixel, assuming 24-bit colour) * 30 (frames per second) = just over 1.5GB/sec (or 12Gbit/sec). That's the data rate that will need to come out of whatever decoder you're using, and that's a lot of data. 10 seconds worth (uncompressed, excluding any overhead) is nearly 15GB.

For comparison, consider that you can get a few hundred MB/sec from an SSD (OCZ claim up to to 550MB/sec with the OCZ Agility 3 range), but that is likely to be somewhat dependent on your usage pattern.

-spxl