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Can 2 4870's fit into a Octo Nahalem

M

MnkyPwz

macrumors member
Original poster
Mar 6, 2009
31
0
So after being on the phone with Apple for about 2.5hours I was told that the Nahalem doesn't asupport 2 buss powered Graphics cards. Is this true, or am I missing something.

I have spent quite some time doing research on the issue of Flashing and what needs I have versus con, and so I bought a 4870. Now I'm told that my Mac Pro only supports one of them. I should also mention that I had purchased a Mac 4870 3months ago with my Mac.

So whats the deal, is this gonna work, or am I screwed?
 
As I understand it there are 2 problems:
1. There is only 300W supplied total to the PCI slots.
2. Each of the four slots can supply 75W (thus you can have four GT 120s if desperate). There are also two (and only two) 6-pin power connectors which can supply 75W each - so, for the 4870, you get 75W from the slot and you still need both the provided power connectors.

So, to run 2 4870s, you need both extra power from somewhere, and extra connectors...

Technically you could have two Quadro 4800s.

Take a look at this thread:
"Running dual 4870's in a 2009 Mac Pro"
https://forums.macrumors.com/threads/665034/

(Apple took 2.5 hours? They answered that one for me in 2.5 minutes.)
 
Short answer - It can be done, but requires some extra connectors, possibly loss of 2nd Optical drive (since you gotta pull the power from there).

The bigger issue is that it doesn't really buy you much...

I needed a 2nd card in order to run extra monitors, so I just picked up a used 2600XT for $75. For OSX use it works fine (although you certainly CAN see the performance difference when moving any sort of window doing OpenGL stuff from one monitor to another when changing cards), and likewise, it works fine in Windows 7, provided I don't try to move anything running DirectX10 from the 4870 controlled monitor over to a 2600XT controlled monitor (since the 2600Xt doesn't support DX10).
 
The Rominator said:
Why do you want 2 of these?

There will be no Crossfire.

You can do it with some power splitters, etc...but not pretty and no real benefit
Click to expand...

Because I wanted to have 3 monitors and the PC 4870 is cheaper than the GT 120.

So what else would you have bought to go with three monitors.
 
MnkyPwz said:
Because I wanted to have 3 monitors and the PC 4870 is cheaper than the GT 120.

So what else would you have bought to go with three monitors.
Click to expand...

As I posted, pick up a 2600XT used....

Especially if you have monitors that use DVI inputs... The 2600XT doesn't require AUX power, and supports 2 DVI monitors.

I run 3 monitors:

1 Dell 2405 FPW - Hooked to the 4870
2 Dell 2007 FP - Hooked to the 2600XT.

Works fine!
 
fjf said:
As I understand it there are 2 problems:
1. There is only 300W supplied total to the PCI slots.
2. Each of the four slots can supply 75W (thus you can have four GT 120s if desperate). There are also two (and only two) 6-pin power connectors which can supply 75W each - so, for the 4870, you get 75W from the slot and you still need both the provided power connectors.

So, to run 2 4870s, you need both extra power from somewhere, and extra connectors...

Technically you could have two Quadro 4800s.

Take a look at this thread:
"Running dual 4870's in a 2009 Mac Pro"
https://forums.macrumors.com/threads/665034/

(Apple took 2.5 hours? They answered that one for me in 2.5 minutes.)
Click to expand...


EDIT: Nevermind. Had a brain fart.
 
If you are unhappy with the performance of the 2600 an 3670 would be an alternative. It will definitely not overload the OD-drive bay power supply. It it kind of pricy though, particularly with a decent cooler on top.
 
I believe you mean a Radeon 3870. It has the added bonus of a working analog mini-DIN port, if you need that.
 
Yes, I meant an ATI Radeon HT3870 Mac&PC Edition. A nice and versatile card but unfortunately with a totally unadequate 1 slot cooler and a slightly heavy price tag if compared with flashed PC cards. Other than that it runs practically in every Mac Pro even when it is crammed with another juice hogging 1st card.
 
Take the new 4870 back! I went thru the same process a few weeks ago. Your onboard Radeon will easily drive 2 monitors with it's two ports (DVI & Mini Display Port). If you want a third monitor get a cheaper PCI graphics card.
 
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