Dual ATI 5870 Graphics Cards in late 2009 Mac Pro?

I currently have an ATI 4870 card in this Mac Pro (late 2009). I use this rig for heavy Adobe Creative Suite 5 and FCP work. I use dual Apple LED 27" monitors.

I'm about to order the 5870 graphics card upgrade from Apple, but before I do, is it possible to run TWO 5870 graphics cards? I am running into conflicting information and trying to get a definitive answer. If yes, do I need additional power cables and if so, which ones?

Alternatively, I've read the 5970 card is essentially two 5870 GPUs on one chip. Will this be a better solution?

I also want the cards to be drop and play ready/natively supported. As I rely on this computer for business, I'm not interested in continually chasing down third-party drivers.

Replies and suggestions much appreciated! Thank you.

toxic said:

thr 5870 requires two power cables. there are only two inputs in the MP motherboard, so you can only install one 5870. the 5770 only uses one power cable, which is why two can be installed.

since there is no 5970 for Mac, you will have to buy a Windows one and flash it to support EFI, if that's even possible, which I don't think it is.

Click to expand...

Thanks toxic. Which is the better path then, two 5770 cards or one 5870? Just curious too, I seem to recall using cable extenders/splitters to add power connections for hard drives and other peripherals on PCs. Is it possible to get molex(?) splitters so I could use the existing two cables to make 4 and thus add two 5870 cards?

Pressure said:

If you can sort the power you can run two Radeon HD 5870 in the Mac Pro.

I would give each card one direct power cable from the logic board and then take the rest of the power from the optical bay.

However you will get no benefit in Mac OS X running two of these graphic cards, only Windows.

Click to expand...

Thank you for the response. As for the no benefit under OS X.. is that because OS X does not support/have drivers for Crossfire? Assuming so, would it still be beneficial to get two cards as I am running two monitors and use one card dedicated to each monitor to slack the load for GPU rendering, etc?

peskaa said:

If your interest lies in OS X your best solution is a pair of 5770 cards. Although each card is basically the same as a 4870 (but with less power draw and heat), you're correct that dedicating a card to each monitor will result in better performance even without Crossfire.

Add in the fact that right now the 5870 is actually worse at OpenGL in OS X then the 5770 and you have a bit of a no-brainer. You would also not have to jury-rig power supplies.

Click to expand...

Thanks peskaa. I think I'm good to go. Going to try two 5770's.