Mining on Mac Pro 2009 4,1 4 GPUs installed won't boot

EddieK420

macrumors member
Original poster
Jan 28, 2009
37
19
Hey guys! I am trying to connect 4 Nvidia GTX GPU's to a 2009 Mac Pro. 3 works fine. But 4 GPU's won't boot.

I started mining ethereum recently and after making a 7 GPU rig I had a couple more GPUs that I bought (gtx 1070s) so I thought I would use my Mac Pro to mine instead of it just collecting dust.

So I have the Mac Pro with 1 1080 Ti inside the case and 2 GTX 1070 outside the case connected through powered PCI riser cards and USB cables. I also have an external PSU.

Everything works like a charm and I get great hashrates using Claymore miner. (using Windows 10).

However the Mac Pro will not boot with 4 GPUs connected (It has 4 PCI slots). 3 GPU works in every configuration GPUs inside the mac pro case or all gpus outside using riser cards also works fine. But as soon as I connect the 4th GPU (another 1070) the Mac Pro won't boot. Just a black screen.

Does anyone here know if 3 Graphics cards is the limit for the 2009 4,1 Mac Pro? (my 4,1 mac pro was firmware upgraded to 5,1).

If 3 GPUs is the Max on the Mac Pro then I guess that's a bummer man that I cant use that 4th PCI slot :(

here is a pic:
IMG_2337.JPG
 
Last edited:

h9826790

macrumors G5
Apr 3, 2014
13,974
6,589
Hong Kong
Hey guys! I am trying to connect 4 Nvidia GTX GPU's to a 2009 Mac Pro. 3 works fine. But 4 GPU's won't boot.

I started mining ethereum recently and after making a 7 GPU rig I had a couple more GPUs that I bought (gtx 1070s) so I thought I would use my Mac Pro to mine instead of it just collecting dust.

So I have the Mac Pro with 1 1080 Ti inside the case and 2 GTX 1070 outside the case connected through powered PCI riser cards and USB cables. I also have an external PSU.

Everything works like a charm and I get great hashrates using Claymore miner. (using Windows 10).

However the Mac Pro will not boot with 4 GPUs connected (It has 4 PCI slots). 3 GPU works in every configuration GPUs inside the mac pro case or all gpus outside using riser cards also works fine. But as soon as I connect the 4th GPU (another 1070) the Mac Pro won't boot. Just a black screen.

Does anyone here know if 3 Graphics cards is the limit for the 2009 4,1 Mac Pro? (my 4,1 mac pro was firmware upgraded to 5,1).

If 3 GPUs is the Max on the Mac Pro then I guess that's a bummer man that I cant use that 4th PCI slot :(

here is a pic:
View attachment 711297
From memory, it's all about max GPU number, but not graphic card number. 8 GPU is the max
 

Flint Ironstag

macrumors 65816
Dec 1, 2013
1,105
594
Houston, TX USA
Apple shipped mac pros with 4 GPUs. Barefeats and others have also tested Cubix expansion boxes with the same or more GPUs.

It's possible, not sure what your issue may be. Folks are usually quick to eliminate flaky risers from the equation.
 

MarkC426

macrumors 6502a
May 14, 2008
982
287
UK
Let me make it clear that I am in no way interested in Mining myself.

I dont consider myself to be 'unintelligent', but can someone please explain in (short form) and lamens terms what the heck it actually means.

I have looked through wiki's etc, but that just confuses me even more as I have never done any programming.
I cant get my head around what actually is the gpu doing and to what and where?

Apologies if i'm the dunce in the class, but as i'm having to wait indefinitely for my new gpu to ship, I think I deserve to know.

Edit: I did read in another thread someone was given an estimate of December for an rx580
 
Last edited:

Synchro3

macrumors 68000
Jan 12, 2014
1,978
833
Let me make it clear that I am in no way interested in Mining myself.

I dont consider myself to be 'unintelligent', but can someone please explain in (short form) and lamens terms what the heck it actually means.

I have looked through wiki's etc, but that just confuses me even more as I have never done any programming.
I cant get my head around what actually is the gpu doing and to what and where?

Apologies if i'm the dunce in the class, but as i'm having to wait indefinitely for my new gpu to ship, I think I deserve to know.

Edit: I did read in another thread someone was given an estimate of December for an rx580
-> https://forums.macrumors.com/thread...rumors-and-info.2056361/page-12#post-24863402

-> https://forums.macrumors.com/thread...rumors-and-info.2056361/page-12#post-24864365
 
Jul 4, 2015
4,488
2,548
Paris
Just forget about buying hardware for mining. Even the Bitcoin and Ethereum Dev teams face palm themselves hard when they see people paying for mining hardware at this stage when the difficulty is so high.

All the sensible people just join an exchange and trade. In fact, it was always cheaper to just buy Ether. But without the mining farms there wouldn't be Ether to buy.

And we still don't know if this is all just a big waste of time. People are claiming they became millionaires, but they haven't cashed out. When they do try to cash out they cause flash crashes on the exchanges.
 

Draeconis

macrumors 6502a
May 6, 2008
968
264
Hey guys! I am trying to connect 4 Nvidia GTX GPU's to a 2009 Mac Pro. 3 works fine. But 4 GPU's won't boot.

I started mining ethereum recently and after making a 7 GPU rig I had a couple more GPUs that I bought (gtx 1070s) so I thought I would use my Mac Pro to mine instead of it just collecting dust.

So I have the Mac Pro with 1 1080 Ti inside the case and 2 GTX 1070 outside the case connected through powered PCI riser cards and USB cables. I also have an external PSU.

Everything works like a charm and I get great hashrates using Claymore miner. (using Windows 10).

However the Mac Pro will not boot with 4 GPUs connected (It has 4 PCI slots). 3 GPU works in every configuration GPUs inside the mac pro case or all gpus outside using riser cards also works fine. But as soon as I connect the 4th GPU (another 1070) the Mac Pro won't boot. Just a black screen.

Does anyone here know if 3 Graphics cards is the limit for the 2009 4,1 Mac Pro? (my 4,1 mac pro was firmware upgraded to 5,1).

If 3 GPUs is the Max on the Mac Pro then I guess that's a bummer man that I cant use that 4th PCI slot :(

here is a pic:
View attachment 711297
Are you giving them all enough power?
 

Fl0r!an

macrumors 6502a
Aug 14, 2007
906
526
From my memory this is normal behavior with more modern GPUs (Maxwell and Pascal, maybe even Kepler). Have seen similar reports from people building CUDA rendering rigs.
 
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SteveJobzniak

macrumors 6502
Dec 24, 2015
489
769
And we still don't know if this is all just a big waste of time. People are claiming they became millionaires, but they haven't cashed out. When they do try to cash out they cause flash crashes on the exchanges.
Bitcoin a waste of time? Are you kidding me?! Bitcoin is great! It's the currency of the future! Just look at all the drugs, guns, childporn, hitmen and human trafficking you can buy with it! That's practically every foodgroup a growing boy needs! Who cares if "Bitcoin millionaires" can't cash it out to real, actually useful money instead?!

[/sarcasm]
 

Supersoberguy

macrumors newbie
Jun 5, 2017
25
2
Almaty, Kazakhstan
Hey guys! I am trying to connect 4 Nvidia GTX GPU's to a 2009 Mac Pro. 3 works fine. But 4 GPU's won't boot.

I started mining ethereum recently and after making a 7 GPU rig I had a couple more GPUs that I bought (gtx 1070s) so I thought I would use my Mac Pro to mine instead of it just collecting dust.

So I have the Mac Pro with 1 1080 Ti inside the case and 2 GTX 1070 outside the case connected through powered PCI riser cards and USB cables. I also have an external PSU.

Everything works like a charm and I get great hashrates using Claymore miner. (using Windows 10).

However the Mac Pro will not boot with 4 GPUs connected (It has 4 PCI slots). 3 GPU works in every configuration GPUs inside the mac pro case or all gpus outside using riser cards also works fine. But as soon as I connect the 4th GPU (another 1070) the Mac Pro won't boot. Just a black screen.

Does anyone here know if 3 Graphics cards is the limit for the 2009 4,1 Mac Pro? (my 4,1 mac pro was firmware upgraded to 5,1).

If 3 GPUs is the Max on the Mac Pro then I guess that's a bummer man that I cant use that 4th PCI slot :(

here is a pic:
View attachment 711297
Hey EddieK420, I'm in a kind of similar situation, including the hardware of yours. But, lucky you, you ended up turning on 3 GPU's, but I can't even turn them on... Only 2 work flawlessly. And it doesn't matter, whether they are working in a case, or outside via riser. Only slots 1 and 2 are working (bottom two slots). If I try to connect only 1 GPU into slot 3, it doesn't get recognized. Thus, if the combination is slot 1+2+3 = nothing works.

Would be very glad and thankful if someone could share the experience and thoughts on this topic. It is a bummer for another GPU not to be used anywhere else...
 

William_si

macrumors regular
Apr 4, 2016
188
53
Croatia
From former testing: Yes, a 4,1 does not boot with 4 GPUs.

I tried various combinations, as base:

280X flashed inside, 3 270X external on x1 risers in 2-4

Switched external with 285, 290X, 370 did not result in changes; it would boot with 3 and an XFX 270X that usually would not boot at all but not detect the card at all.

PLX splitting slot 4 to 4x x1 (Amfeltec splitter) did not change that 4 did not work, neither did mixing with Nvidia or trying 280X and 3 RX470/480.

As with the PLX on slot 4 i can get 2 external GPUs, 1 internal, USB3 in slot 3 and SQUID with 2 SSDs in slot 2 plus an external Intel NIC on the PLX this seems to be a GPU specific limit, not a PCIe addressing one (i have a Tyan 5520 based dual 1366 board very similar to a 4,1 which will stop booting at exactly 8 cards, regardless what).
 

Supersoberguy

macrumors newbie
Jun 5, 2017
25
2
Almaty, Kazakhstan
After quite some time I also do confirm the following:
  • Mac Pro 4,1 (flashed to 5,1) is capable of 3 GPU only, it boots, it works, it mines. It may be 1 GPU inside, 2 on risers; or all 3 GPU on risers. The order of the PCI-E slots does not matter. With 4 GPU's the chime does not come and the whole system is just working the fans, but not the system. Nothing happens.

  • Mac Pro 1,1 (flashed to 2,1) is capable of 2 GPU only. It does not matter, whether the GPU's are installed inside the Mac Pro, or through risers. The order of the PCI-E slots also doesn't matter. I have two Mac Pro's 1,1, one of which is flashed to 2,1 and the other one is in the stock position. Neither of them can chime at startup with 3 GPU's.

Maybe this will help somebody in the future.
 
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h9826790

macrumors G5
Apr 3, 2014
13,974
6,589
Hong Kong
After quite some time I also do confirm the following:
  • Mac Pro 4,1 (flashed to 5,1) is capable of 3 GPU only, it boots, it works, it mines. It may be 1 GPU inside, 2 on risers; or all 3 GPU on risers. The order of the PCI-E slots does not matter. With 4 GPU's the chime does not come and the whole system is just working the fans, but not the system. Nothing happens.

  • Mac Pro 1,1 (flashed to 2,1) is capable of 2 GPU only. It does not matter, whether the GPU's are installed inside the Mac Pro, or through risers. The order of the PCI-E slots also doesn't matter. I have two Mac Pro's 1,1, one of which is flashed to 2,1 and the other one is in the stock position. Neither of them can chime at startup with 3 GPU's.

Maybe this will help somebody in the future.
Does anyone remember if we can order a 4xGT120 4,1 when Apple still selling them? I just wonder do they offer this option.
 
Last edited:

LightBulbFun

macrumors 68020
Nov 17, 2013
2,224
2,081
London UK
The issue with the multiple GPUs,

is not that the Mac Pro 1,1-5,1 cant work with 4 GPUs, its down to which GPUs you use and how said GPUs use certain memory spaces in the firmware, I dont remember the exact specifics but i know modern cards can cause issues when you use a lot of them in one system, also keep in mind that a Modern GPU is 2 PCIe devices, theres the GPU it self and then theres the HDMI/DP audio controller so that probably aint helping the mater LOL. for the record heres a screen shot of me running 4 GPUs in my Mac Pro (when I replaced the GeForce 210 with a GT 740 the machine would post but not boot OS X) I know that there are some older posts in the forums by the likes of @Tutor where they go into detail over which GPUs the Mac Pro plays best with and the whole memory address space issue (and they also mention some PC motherboards that run into the same issues) also the Mac Pro 1,1/2,1 did have a BTO option for 4 7300 GTs.

hopefully this can help you resolve your issues :)

Screen Shot 2017-08-14 at 18.58.00.png
 

Supersoberguy

macrumors newbie
Jun 5, 2017
25
2
Almaty, Kazakhstan
Yes, thank you for the info. I forgot to mention, that older GPU's work great in 1,1/2,1, all 4 slots are loaded and can be used. I had 7300's if I remember correctly, and these were rock solid and worked just fine. IDK the deal with GT120's and 4,1/5,1 situation.

The problem is with the newer one's. In my case, 4 1060's 6GB cannot be used at the same time. The machine will only boot with only 3 of these GPU's.
 
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