2 Radeon 4870's possible?

[2002cbr600f4i]

Looking at buying the new Core i7 based Mac Pro... thinking the 4 core with 8 GB Ram...

I'm a programmer, and my current (older) windows box has 2 video cards so I can drive my 3 monitors which is VERY nice when programming. I also game, so I want the better Radeon 4870 graphics card...

My question is, is it possible to put a 2nd 4870 into the Mac Pro? I know you can't order it configged that way, but you can order the 2nd card (4-5 week wait).

I tried asking both the Apple online sales chat support, and the applecare tech support people and neither really had an answer (in fact, some of the stuff they told me was absolutely ludacris... Like "If you order it with the Raid card and the fiber channel card, then you can use 2 radeons" (which is impossible because there's only 4 slots and you'd need 6 to run all that!)

On the apple forums there's a thread where somebody said it's not possible to run 2 4870's because the bus can only provide 300W and 2 4870's require more than that.

Anyone know what the deal is here? Could I possibly just get a 2600XT as the 2nd card instead? Will that work?

Honestly, under Windows, I only really need the 1 monitor (24" Dell 2405FPW) but under OSX, I want to have my desktop stretched across all 3.

 

[Tallest Skil]

There are five slots, not four. It is still physically impossible.

Please search the forums. This is only possible with a second PSU in the second ODD bay, and all of your PCIe slots will be used.

 

[2002cbr600f4i]

There are five slots, not four. It is still physically impossible.

Please search the forums. This is only possible with a second PSU in the second ODD bay, and all of your PCIe slots will be used.

Whoa, wait a second, I see in your sig you have both a 4870 and a GT 120? that works? I didn't think you could mix like that!

 

[goMac]

Why do you need two 4870's for gaming?

Are you planning on running a game on all three displays?

 

[Tallest Skil]

Whoa, wait a second, I see in your sig you have both a 4870 and a GT 120? that works? I didn't think you could mix like that!

'Course you can.

Vista won't run, but OS X, XP, and Windows 7 are perfectly fine with it.

 

[VirtualRain]

It's definitely possible to run 2 4870's... https://forums.macrumors.com/threads/665034/

Powering the card is the only issue but that's easily solved by getting a couple of adapter cables and running power down from the unused optical bay sata power connector.

 

[2002cbr600f4i]

Why do you need two 4870's for gaming?

Are you planning on running a game on all three displays?

Ok, since this is discussed elsewhere, let's just close this thread out by saying:

I only want 2 4870's for:

1) desktop stretched across all 3 monitors in OSX, and for the OpenCL advantages in Snow Leopard. And so I don't get varying performance when moving windows from one display to another.

2) under windows, I really only *need* the 24" display to run, but it would be helpful to be able to drive all 3 (you'd be amazed how much nicer it is to play Flight Simulator X with all the various sub-panels open, a good flight management program and weather system open, and other various programs running on the side displays...)