Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

blackwoodfx

macrumors member
Original poster
Nov 15, 2010
76
3
Las Vegas, NV
Interesting update to this thread. I've been using the very same setup that I provided the above instructions, going on about a month and a half now.

What I've found is that if I leave the Crossfire connection cables attached to the graphics cards, while booting into the Apple OS X environment, startup performance is significantly reduced. It seems to take upwards of about 3-5 minutes before everything settles.

This is a bit of convenience problem because the SLI support in Windows 7 by dual booting with Boot Camp is superb. Games and programs are buttery smooth. While in the OS X environment, you cannot use SLI but the second graphics card is recognized and utilized by rendering apps.

The best thing then appears to be manually connecting/disconnecting, when you are booting into the Win7 or OS X environment.
 

ActionableMango

macrumors G3
Sep 21, 2010
9,612
6,907
That's unfortunate.

Didn't someone test this and crossfire works without the bridge anyway, for only a very slight performance decrease? If so, it might be worth it just to leave the bridge off all the time.
 

MacHamster68

macrumors 68040
Sep 17, 2009
3,251
5
sure the two graphic cards are getting recognized by OSX and the apps too , thats nothing new you could do that already in PowerMac's fitting two graphic cards but as two independent graphic cards , so no need for crossfire/sli graphic cards for example to drive multiple monitors , but the whole idea behind a sli /crossfire setup is that the two graphic cards work together as one that what the bridge is for that connect the two cards , otherwise it would be pointless to spend the money on sli/crossfire graphics card's as this mod actually only is of use for people running windows and use the MacPro as a posh gaming rig or?
 
Last edited:

ActionableMango

macrumors G3
Sep 21, 2010
9,612
6,907
You misunderstand me. I've read many times that Crossfire can still work without the crossfire bridge, with performance only very slightly slower than crossfire with the bridge.

In fact, I've seen Crossfire-compatible cards that don't even have a Crossfire bridge connector.

So what I'm asking is, will this particular setup work without the bridge and still have Crossfire working?
 

MacHamster68

macrumors 68040
Sep 17, 2009
3,251
5
ys you did misunderstood me a bit , sure osx is able to work with the two cards, but i guess you will lose quiet a bit performance if these cards had been made to work with a crossfire bridge , but maybe someone with this setup
could just connect the bridge and under windows do geekbench/xbench or whatever results and under osx without the bridge do geekbench/xbench results again then we might see how many percent the results improve or drop and if it would not be wiser to get a better single GPU instead if you only run OSX , i meant why pay for two if one would offer better performance (if the card gets supported under osx that is )i have a radeon 6970 xfx with 2gb ddr5 vram for example in a gaming rig i just setup and i am pretty sure it might outperform the the two 5870's and i am able to drive 3 displays with the single card , but it to offers crossfire

would be interesting to know as i plan to get a MacPro , as i am fed up with consumer models that are not user upgradeable and only offer mobile gpu's ,i feel the MacPro is the way to go as it offers the option to stay longer up to date with just some upgrades without having to fear to rip some wires /cables inside , so make it worth to spend the cash as i see it on my PowerMac G5 2.3 dual core which is still even by today standards a great computer only with OS limitations which do not really bother me that much anyway as i like classic so i am a tiger fan anyway
 
Last edited:

dp84

macrumors member
Aug 14, 2010
51
0
from applecomponents.com

Power Supplies
661-5449
$239.00
In Stock
Power Supply, 980 W, EUR LOT 6
Mac Pro (Mid 2010) · Mac Pro (Early 2009)

Does it mean that all models (4c, 8c, 12c) have the same PSU?? :eek:
 

DeafNeoMac

macrumors newbie
Jul 17, 2010
4
0
What about the heat issues?

I have been surfing the net trying to find information on whether if it's worth it to install two ATI Radeon HD 5870 into Mac Pro or just build a dedicated gaming rig. I am glad to see this posting up about 2x ATI card already installed in details of how it should be done.

For some of you out there might still be having trouble in locating a dedicated power supply for video cards only: Here's the name of it Fsp Booster X. Although it's in the ranges of 80 bucks.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104054&Tpk=FSP Booster

Now really-I am very curious about the heat issues of having the videocard so closed together or literally sitting on top of it. What's the temp of the cards running in idle mode and load mode?

I want to know in OS X and Win 7 environment.

Here's a scoop of why I would ask about this and what I do: Well I'm basically a video editor for a non profit organization. I'll use the laptop (from work) for on the road editing while the (my personal set up) Mac Pro rig for heavy duty editing at home office.

During my down time is that I also like to game. The games I play are Crysis, Warhead, Black Ops, Fortress II, Ghost sniper, Crysis II (when it comes out :D) and Brink the Game when it comes out in May. (There are other games listed in my steam account as well but these are the majors that I play)

So that being said: How's the heat issue of two ATI 5870 sitting on top of one another as for heavy load and idling?
 

Transporteur

macrumors 68030
Nov 30, 2008
2,729
3
UK
For some of you out there might still be having trouble in locating a dedicated power supply for video cards only: Here's the name of it Fsp Booster X. Although it's in the ranges of 80 bucks.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104054&Tpk=FSP Booster

*Cough* *Cough* Should have read first post. *cough* :rolleyes:

PARTS LIST

2. You'll also need a 5.25" power supply to power the second card as each of the 5870's require x2 of the 6-pin 12V plugs. This is the one I purchased:
http://www.newegg.com/Product/Produ...1044&cm_re=modular_psu-_-17-101-044-_-Product
 

Transporteur

macrumors 68030
Nov 30, 2008
2,729
3
UK
Considering that a 5870 has a maximum power consumption of about 212W (source), and the fact that the PCIe slot itself provides up to 75W, a 300W PSU will certainly be fine.
 

scottsjack

macrumors 68000
Aug 25, 2010
1,906
311
Arizona
Great Work!

Not that I'm going to do this with my 2010 3.2 quad/5870 but it's really nice to see someone do great mod work and then to be able to explain it so thoroughly.

The MacRumors Mac Pro Forum is so interesting to read compared to all the other iToys stuff found at Mac sites online.
 

blackwoodfx

macrumors member
Original poster
Nov 15, 2010
76
3
Las Vegas, NV
Quick update to confirm Apple OS X Lion has no issues with this mod. I've also updated my own configuration. Now sporting 3x Apple LED 27" monitors, swivel stands that rotate 90 degrees for a combined resolution of 7680x1440 (h) or 4320x2560 (v).

This could be increased with additional monitors. x2 DVI's and 1x DisplayPort's are left open on cards.

When/if I ever switch over to Windows 7, I pull the center monitor forward about 3" and rotate to horizontal.
 
Last edited:

fouel

macrumors member
May 14, 2008
68
1
Make it easy

Quick update to confirm Apple OS X Lion has no issues with this mod. I've also updated my own configuration. Now sporting 3x Apple LED 27" monitors, swivel stands that rotate 90 degrees for a combined resolution of 7680x1440 (h) or 4320x2560 (v).

This could be increased with additional monitors. x2 DVI's and 1x DisplayPort's are left open on cards.

When/if I ever switch over to Windows 7, I pull the center monitor forward about 3" and rotate to horizontal.

Place two 5870 cards into mac pro is eazy.
1.Two 5870 cards.
2.Two cables like this:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180699770980&ssPageName=STRK:MESELX:IT
 

VirtualRain

macrumors 603
Aug 1, 2008
6,304
118
Vancouver, BC
Yeah, little power problem there fouel. Not enough juice in the supply. Hence, the instructions posted here. But thanks for your input.

Has anyone been brave enough to try this? It might work. The Apple PSU with 980W on tap, certainly has enough juice (especially in a quad). The question is: can the traces on the motherboard handle the added current draw? To what spec where they designed? How over engineered are they? I suppose the risk of frying your main board is enough to discourage anyone from trying it.
 

blackwoodfx

macrumors member
Original poster
Nov 15, 2010
76
3
Las Vegas, NV
Has anyone been brave enough to try this? It might work. The Apple PSU with 980W on tap, certainly has enough juice (especially in a quad). The question is: can the traces on the motherboard handle the added current draw? To what spec where they designed? How over engineered are they? I suppose the risk of frying your main board is enough to discourage anyone from trying it.
Not sure how you figure the default PSU has enough power on tap. Each of the Radeons draw 350w at use and have a 500w ceiling requirement. There is not enough juice available. And yes, I have and a few others have also tried this.

Stick with the plans I offered here.
 

creidv

macrumors newbie
Jul 4, 2011
5
0
I'm about to go from a gt120 to a 5770 to shorten rendering in FCP, and was wondering if the 5870 (one) would be a better choice, and would your double setup be significantly better yet?
mp 4.1, 2.26 quad, 16 gb, mid 2010.
mahalo
 
Last edited:

Spacedust

macrumors 6502a
May 24, 2009
999
160
Hi, can you check if Crossfire is working properly under Windows 7 64-bit ?

I got BSOD on two HD5770's with Catalyst drivers newer that 10.11.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.