Early-2009 Mac Pro - The GPU Dilema

[GeneralAntilles]

Thanks to a leaky G5 I've netted myself a new dual-2.26GHz Mac Pro. I went ahead and ordered a Radeon HD 4870 from Apple, but I need another graphics card to go with it. It looks like I have a number of options:

1. Second Radeon HD 4870 - This is an appealing option because it offers a lot of performance, but it's also prohibitively expensive and eats up two PCI slots between the heatsink and the power supply.
2. GT 120 - The only supported option, but the Mini DisplayPort on the GT 120 and its anemic performance make it less than desirable, but it is single-slot.
3. Radeon HD 3870 - Seemingly a nice compromise between options 1 and 2, but it would require figuring out a workable power arrangement (4-pin Molex to 6-pin PCIe adaptor off the 2nd optical bay?) and the reports of excessive fan noise are off-putting. It's priced similarly to the GT 120, however (when you add in the Mini DisplayPort adaptor) and actually provides two dual-link DVI ports while still maintaining the single-slot form factor.

I went ahead and ordered a GT 120 since I suspect I can make use of a 3rd graphics card anyway, but am still wondering whether the 3870 would make a more desirable secondary card.

 

[Dr.Pants]

Thanks to a leaky G5 I've netted myself a new dual-2.26GHz Mac Pro. I went ahead and ordered a Radeon HD 4870 from Apple, but I need another graphics card to go with it. It looks like I have a number of options:

Running more than two displays? Just curious.

1. Second Radeon HD 4870 - This is an appealing option because it offers a lot of performance, but it's also prohibitively expensive and eats up two PCI slots between the heatsink and the power supply.
2. GT 120 - The only supported option, but the Mini DisplayPort on the GT 120 and its anemic performance make it less than desirable, but it is single-slot.
3. Radeon HD 3870 - Seemingly a nice compromise between options 1 and 2, but it would require figuring out a workable power arrangement (4-pin Molex to 6-pin PCIe adaptor off the 2nd optical bay?) and the reports of excessive fan noise are off-putting. It's priced similarly to the GT 120, however (when you add in the Mini DisplayPort adaptor) and actually provides two dual-link DVI ports while still maintaining the single-slot form factor.

1. Its a trap!* The second 4870 will require another PSU, methinks that was the general consensus here. You can fit one in the second optical bay that is made for that form factor.

2. Be careful if you plan to run Windows Vista native - it doesn't like the mix-and-match of ATI and nVidia GPUs (wheras 7 and Xp do like both, IIRC)

3. Maybe the second PSU again? I am not sure how people have fitted this in their MacPro.

I went ahead and ordered a GT 120 since I suspect I can make use of a 3rd graphics card anyway, but am still wondering whether the 3870 would make a more desirable secondary card.

Not sure - I can remember reading around here that the 3870 was not OpenCL capable, something to keep in mind. J the Ninja posted this.

Have you considered flashing any of the above cards? Also, what uses will your computer be put towards?

*I understand that Antilles and Ackbar are two different characters, but I couldn't help it

 

[GeneralAntilles]

Running more than two displays? Just curious.

Probably 4 or 5 depending. Two Samsung 2343bwxs, a Samung 206bw, a Samsung SyncMaster 941bw and a 20" 1st-generation aluminum Apple Studio Display.

It obsoletes Exposé.

1. Its a trap!* The second 4870 will require another PSU, methinks that was the general consensus here. You can fit one in the second optical bay that is made for that form factor.

Yes, I'm aware of the power requirements, thus the issue of it absorbing all of the additional PCI slots. It's out thanks to the cost and double-wide heatsink anyway.

2. Be careful if you plan to run Windows Vista native - it doesn't like the mix-and-match of ATI and nVidia GPUs (wheras 7 and Xp do like both, IIRC)

Yeah, I could care less about Windows, but thanks for the heads up.

3. Maybe the second PSU again? I am not sure how people have fitted this in their MacPro.

That might be an issue, although it only requires one additional 6-pin PCIe connection (versus the 4870's 2), so it seems like powering it off the optical bay should be feasible.

Not sure - I can remember reading around here that the 3870 was not OpenCL capable, something to keep in mind. J the Ninja posted this.

A notch against the 3870, then.

Have you considered flashing any of the above cards?

I have, but so far my impression has been that the flashed cards are only capable of outputting video on a single DVI connection which makes them mostly unusable for my purposes. However if this is not the case, then I'd love to be able to save the money.

Also, what uses will your computer be put towards?

Everything from text editing to 3D rendering and gaming. I have no issue maxing pretty much any hardware I can get my hands on.

 

[Dr.Pants]

Probably 4 or 5 depending. Two Samsung 2343bwxs, a Samung 206bw, a Samsung SyncMaster 941bw and a 20" 1st-generation aluminum Apple Studio Display.

It obsoletes Exposé.

For certain! I can't think of SPACE for those displays on my desk without ergonomics.

Yes, I'm aware of the power requirements, thus the issue of it absorbing all of the additional PCI slots. It's out thanks to the cost and double-wide heatsink anyway.

Nope, just one. Take a look. The GT120 at the bottom is in the first slot, and there is space for a double-wide card.

That might be an issue, although it only requires one additional 6-pin PCIe connection (versus the 4870's 2), so it seems like powering it off the optical bay should be feasible.

Certainly, but I don't know the requirements of the 3870 off the top of me head, but certainly do-able.

A notch against the 3870, then.

A very unfortunate one, IMHO

I have, but so far my impression has been that the flashed cards are only capable of outputting video on a single DVI connection which makes them mostly unusable for my purposes. However if this is not the case, then I'd love to be able to save the money.

I was under the impression that the flashed 4870s could use dual-DVI but lose the ability to output VGA.

Everything from text editing to 3D rendering and gaming. I have no issue maxing pretty much any hardware I can get my hands on.

Heh. Awesome. Might consider a processor upgrade People do it (as well I next year). However, the dual-core system looks trikier to upgrade then the quad....

 

[GeneralAntilles]

For certain! I can't think of SPACE for those displays on my desk without ergonomics.

One monitor arm, a speaker, some monitor stacking and a little bit of desk modding.

Nope, just one. Take a look. The GT120 at the bottom is in the first slot, and there is space for a double-wide card.

Sadly, yep. The Two Radeons occupy slot 1 and 2, the heatsink on the second covers slot 3 and the power cable for the optical-bay PSU covers 4. See here and here.

I was under the impression that the flashed 4870s could use dual-DVI but lose the ability to output VGA.

Ah, maybe it is that. Dunno, but it'd be nice to have an authoritative answer.

Heh. Awesome. Might consider a processor upgrade People do it (as well I next year). However, the dual-core system looks trikier to upgrade then the quad....

Considering it when the 5500-series prices come down next year. Although the potential for failure scares me a bit on the dual-CPU machines.

 

[J the Ninja]

<snip>
A notch against the 3870, then.
<snip>

Keep in mind, I'm just an armchair poster on this sort of thing. I don't know how to code OpenCL.. I'd like to learn, but I have no idea how hard it would be. (Good God, I really don't know Python. Or CSS for that matter). I don't claim that thread to be 100% correct. How I became the some sort of OpenCL expert for this fora is a bit of a mystery to me. As a note, I've read some other statements (that I really didn't understand) which said the HD 3000 series isn't OpenCL capable. Although it does have programmable shaders, it's lacking some other features that are pretty much essential. Supposedly these aren't totally implemented on the HD 4000 series either, and this is responsible for their abysmal OpenCL performance.

 

[Dr.Pants]

Sadly, yep. The Two Radeons occupy slot 1 and 2, the heatsink on the second covers slot 3 and the power cable for the optical-bay PSU covers 4. See here and here.

If you need the PCIe x4 lane on top, couldn't one route power through the front of the bay? I know, tacky, but hey, if it works....

 

[JesterJJZ]

Just get a second Mac Pro and sit it next to the one you got.

 

[GeneralAntilles]

If you need the PCIe x4 lane on top, couldn't one route power through the front of the bay? I know, tacky, but hey, if it works....

Yeah, or I bet I could probably dremel the heat exhausts on one of the 4870's to slip the cable through there, too. Either way, not enough money.

Just get a second Mac Pro and sit it next to the one you got.

Yeah, but a second Mac Pro wouldn't be coming on-the-house from Apple.

 

[matthewtoney]

Thanks to a leaky G5 I've netted myself a new dual-2.26GHz Mac Pro. I went ahead and ordered a Radeon HD 4870 from Apple, but I need another graphics card to go with it. It looks like I have a number of options:

1. Second Radeon HD 4870 - This is an appealing option because it offers a lot of performance, but it's also prohibitively expensive and eats up two PCI slots between the heatsink and the power supply.
2. GT 120 - The only supported option, but the Mini DisplayPort on the GT 120 and its anemic performance make it less than desirable, but it is single-slot.
3. Radeon HD 3870 - Seemingly a nice compromise between options 1 and 2, but it would require figuring out a workable power arrangement (4-pin Molex to 6-pin PCIe adaptor off the 2nd optical bay?) and the reports of excessive fan noise are off-putting. It's priced similarly to the GT 120, however (when you add in the Mini DisplayPort adaptor) and actually provides two dual-link DVI ports while still maintaining the single-slot form factor.

I went ahead and ordered a GT 120 since I suspect I can make use of a 3rd graphics card anyway, but am still wondering whether the 3870 would make a more desirable secondary card.

Since you are apparently running the same config as myself (single 4870 combined with a GT120) care to comment on *any* games you have tried or possible usage of VMware Fusion? I'm trying to confirm what seems likely as a conflict with these two cards combined.

 

[GeneralAntilles]

Since you are apparently running the same config as myself (single 4870 combined with a GT120) care to comment on *any* games you have tried or possible usage of VMware Fusion? I'm trying to confirm what seems likely as a conflict with these two cards combined.

Still waiting on my Mac Pro to ship from Apple. They quoted me another 7-10 days. :\

 

[GeneralAntilles]

Just to update, I ordered the GT 120 and have an in on a cheap 3870, so I'll run some tests and see what's what once everything gets here.

 

[TheStrudel]

I would point out that a Radeon 2600 will work just fine with the 4870. And plenty of people have successfully flashed 4870s that work with two displays, and a lot of the people who only had them working with one DVI port found that problem magically fixed by Snow Leopard.

Also, people have run two 4870s with no additional PSU - just by using a Y-splitter on the PCIe power traces from the logic board, no molex connectors involved. There was a whole thread on this.

 

[Justinf79]

Sadly, yep. The Two Radeons occupy slot 1 and 2, the heatsink on the second covers slot 3 and the power cable for the optical-bay PSU covers 4. See here and here.

I noticed in the pic that the two cards are hooked up in crossfire. Does OS X support crossfire, or is that just for windows?

 

[Whiteyez]

I noticed in the pic that the two cards are hooked up in crossfire. Does OS X support crossfire, or is that just for windows?

OS X does not support crossfire or sli, only windows.