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Running dual 4870's in a 2009 Mac Pro

Crossfired 4870's in an '06

So I used the lower optical drive to run a Molex down and out where a Y-Splitter took a connection each to a 4870. The other 4870 connection was from the proper power cords plugged into the Mainboard.

I used The PCIE slot utility and set each of 1 & 2 at 8X.

Crossfire showed up as an option on the ATI Catalyst panel.

Engaged...and Crysis performance went straight to hell.

I tried the same thing some time ago with 2@ 3870 and got same result.

Will run 3DMark 06 and see if there is a difference there.
 
matthew.russo said:
Because Apple computers are not meant for gaming...
Click to expand...


What are they meant for ? Does it say somewhere on the Apple website that they aren't for gaming ? I didn't say anything about gaming. What does having the the ability to choose from more that two video cards have to do with gaming ?
 
So, Crysis may not care for 4870s Crossfired...but 3DMark got a boost from it.

With Single 4870 I got 12,800 and with them running in Crossfire I gained 1000 points and got 13,800.

So, maybe just a Crysis incompatability?
 
The Rominator said:
So, Crysis may not care for 4870s Crossfired...but 3DMark got a boost from it.

With Single 4870 I got 12,800 and with them running in Crossfire I gained 1000 points and got 13,800.

So, maybe just a Crysis incompatability?
Click to expand...

I'm not too familiar with 4870's in Crossfire, but isn't that pathetic?

Do ATI cards need a crossfire connector like nvidia SLI setups... you know... a bridge across the top of the cards as an exclusive data path?
 
VirtualRain said:
I'm not too familiar with 4870's in Crossfire, but isn't that pathetic?

Do ATI cards need a crossfire connector like nvidia SLI setups... you know... a bridge across the top of the cards as an exclusive data path?
Click to expand...

They sure do. It's called a crossfire interconnect cable. Bit odd for Crysis to do that...maybe it is because of the bus speed settings.
 
The Rominator said:
So, Crysis may not care for 4870s Crossfired...but 3DMark got a boost from it.

With Single 4870 I got 12,800 and with them running in Crossfire I gained 1000 points and got 13,800.

So, maybe just a Crysis incompatability?
Click to expand...

That's definitely not what I'm seeing in Crysis on a MP'08 (Very High settings at 2560x1600 become playable w/ Crossfire). The only difference I can think of is that the cards are running on two 2.0 x16 slots, but I don't think it should affect the tests that much...
 
I am very curious to see how Os X reacts to the Crossfire bridge. I am on the fence flashing 2 4870 cards and sell my gaming rig. Somehow I have a bad feeling about this because Apple does not support Crossfire in any way.:(
 
Matrixfan said:
I am very curious to see how Os X reacts to the Crossfire bridge. I am on the fence flashing 2 4870 cards and sell my gaming rig. Somehow I have a bad feeling about this because Apple does not support Crossfire in any way.:(
Click to expand...

OS X ignores the CrossFire bridge on my 2x 2600XTs.
 
Opps, sorry, I may have misread the topic a bit, I am in a hurry right now.:eek:
Let me rephrase the question: does the Crosfirre Bridge cause any problems under Mac OS X when not gaming in Windows?
 
I've been following this thread for a little while now as I'm interested in crossfire to play Empire: Total War on max settings (highly recommend that game by the way).

So is there a verdict yet? Can Crossfire be done in Windows without screwing up OS X? There seems to still be some discussion about power draw issues. What about the type of card you can use? ie I have an '09 mac pro with the apple-provided 4870. Could I combine that with a normal pc 4870? Do they both have to be 512MB vRAM or can the new one be 1GB (or does the extra 512 not matter)?

Sorry for the noobtastic questions but I haven't been into high-end gaming since early college and now i need a little more video power to handle Empire. Any help/clarification you guys could provide would be much appreciated. :D
 
AGDenton said:
I'm only using one. Why don't you take one of yours off? Who knows...:)
Click to expand...

I'm pretty sure it does't work with just one.

Have you then enabled Crossfire in the ATI Catalyst Center? It most certainly doesn't work if it isn't turned on and I don't think you can turn it on with just one cable.
 
The Rominator said:
I'm pretty sure it does't work with just one.

Have you then enabled Crossfire in the ATI Catalyst Center? It most certainly doesn't work if it isn't turned on and I don't think you can turn it on with just one cable.
Click to expand...

Two cables are only used for Crossfire X (i.e. more than 2 cards), although I don't think you should be seeing performance degradation with two. The "Enable Crossfire" checkbox is definitely ticked in the Catalyst Control Center on my end, though.

Another possibility is that Crysis isn't really GPU-bound, but rather bandwidth-bound at your resolution/settings. Have you tried one of the games with a good reputation for multi-GPU scaling, like F.E.A.R. or C.O.D. series?
 
You do not have to use 2 crossfire interconnect cables, it works just fine with 1.
The cards have 2 connectors in case you are running 3 cards, so you can have 1 connector going to each card, looping them all together.
A cable from #1 to #2 and a cable from #2 to #3.
You can run 2 cables between 2 cards but it makes no difference what so ever.

Hope that clears it all up.
 
The tech specs for the 2009 Mac Pro state that there is one 16x PCI-E slot and 2 4x PCI-E slot, but all slots provide mechanical support for 16-lane cards.

What the heck does that mean? Can there only be one 16x card? Is crossfire feasible or not?
 
justflie said:
The tech specs for the 2009 Mac Pro state that there is one 16x PCI-E slot and 2 4x PCI-E slot, but all slots provide mechanical support for 16-lane cards.

What the heck does that mean? Can there only be one 16x card? Is crossfire feasible or not?
Click to expand...

That's three PCIe slots apart from the one used by the graphics card. Which makes it two 16x PCIe, two 4x PCIe in total. Don't panic;).
 
The Rominator said:
So, Crysis may not care for 4870s Crossfired...but 3DMark got a boost from it.

With Single 4870 I got 12,800 and with them running in Crossfire I gained 1000 points and got 13,800.

So, maybe just a Crysis incompatability?
Click to expand...

Just a reminder folks...

3dMark is VERY CPU bound because they run it at a pathetic 1280 x 1024 resolution

Crank up the 3dMark resolution or overclock your CPU, and I guarantee you'll see the scores shoot up
 
The Rominator said:
So I used the lower optical drive to run a Molex down and out where a Y-Splitter took a connection each to a 4870. The other 4870 connection was from the proper power cords plugged into the Mainboard.

I used The PCIE slot utility and set each of 1 & 2 at 8X.

Crossfire showed up as an option on the ATI Catalyst panel.

Engaged...and Crysis performance went straight to hell.

I tried the same thing some time ago with 2@ 3870 and got same result.

Will run 3DMark 06 and see if there is a difference there.
Click to expand...

if you don't mind me asking, what cable did you use to transfer from sata power to molex?

this one perhaps? (or one like it)

http://www.newegg.com/Product/Product.aspx?Item=N82E16812226018

also, how did you route these cables in the case, theres not to many spaces to push things through. a picture or so would be nice, as I am trying to get this to work also with no avail.
 
xsoniccrackersx said:
if you don't mind me asking, what cable did you use to transfer from sata power to molex?

this one perhaps? (or one like it)

http://www.newegg.com/Product/Product.aspx?Item=N82E16812226018

also, how did you route these cables in the case, theres not to many spaces to push things through. a picture or so would be nice, as I am trying to get this to work also with no avail.
Click to expand...

Something like that or what I posted in Post #37 which is available from Performance-pcs.com
 
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