I have the current Mac Pro (8-core 2.8Ghz) with the ATI Radeon 2600 video card. I connected a 2nd monitor to it last night to use with FC. When I launched FC, it generated an error telling me that some of my effects wouldn't work with that video card. I assume that its to much for the card to display on two monitors and handle the effects.
I found this (ATI RADEON 3870 512MB 16x PCIe Video Card f... (100-435928) at OWC (http://eshop.macsales.com/item/ATI%20Technologies/100435928/)) for $218, but there are also other versions of it on Newegg for as little as $100. Are these the same cards and will they work with my Mac Pro?

Video cards need to say specifically that they are made for the mac pro. Apple designed the mac pro to not work with "regular" video cards.

yeah the site you listed above has a section specifically for Macs if you look for it. As far as your current setup, you may want to try running a lower resolution on both monitors...see if that works.

-JS

I have the Octo with the ATI 2600, runnin' 1920x1200 and 1360x768. Never had a problem.

I'm interested in moving up to 2560x1600. Let us know what you're attempting to run it at.

Chad, I had the X1900 XT in my Mac Pro till it started to die (the same way everyone else's have.. even though I been cleaning it with compressed air on a monthly basis since I bought my computer).

Anyhow, I've had that HD 3870 in my Mac Pro for 2-3 months now, and it's working fine. Not sure what's going on with your current card. And yes, you need to buy Mac-specific video cards.

I have the same machine (8 core), with the 2600 stock card and I'm using it to drive 2 x 23" screens (each 1920x1200). No problem whatsoever. I even run FCP, Motion at the same time, sometimes even together with aperture (which has the biggest appetite for graphics card RAM next to motion). I cannot see how your identical hardware config should have problems with FCP. (BTW, I used my old G5 with a Radeon 9600 with 128mb RAM to drive the same two displays, and it didn't have any problems running FCP (much slower of course, but it worked with these two screens at 1920x1200)).

Are you sure you're running the most recent versions? Maybe some other software-related problem with the machine? How much total RAM does it have?

I've been eyeing the 3870 from OWC, since it supposedly gives better performance in both aperture and motion, but so far, I'm waiting, particularly as there's been some reports that the newer generation of cards (4870) might come to Macs early next year.

Best,
Dino