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Jsiegrist

macrumors newbie
Original poster
May 3, 2018
18
5
Specs are
12 core 3.46ghz - 4,1 flashes to 5,1
Rx580 installed with two 6 pin to a dual 6 pin to 8 pin adapter.
48gb ram ddr3 ecc 1333

I’m getting consistent restarts when trying to render out 4k footage in premiere and AE. Takes a few minutes then it will turn off.

I thought it might be overheating, so installed Fan Control and ran the fans full blast. Temps seem ok but still get a hard shutdown.

Pulled the rx580, reinstalled the gt120 and the shutdown problem goes away. Obviously the render now takes way too long to be useable.

Brand new install of High Sierra.

Now I’m thinking maybe it’s the GPU or GPU cable. Any tests you can think of to help me narrow down the problem?

Thanks!
 

danieldavis3924

macrumors member
Jun 9, 2015
40
9
I would start looking at the power supply. It looks like your issues really start when the system is under heavy load.

Power supplies over time lose efficiency, and begin to struggle under high loads. Eventually, they ‘trip’, causing the machine to switch off.

It’s common when a PC user upgrades their graphics card to something like a Nvidia Titan on a 500w PSU whilst mining bitcoin.

Hopefully you find the culprit soon!
 

Jsiegrist

macrumors newbie
Original poster
May 3, 2018
18
5
Ok update. It’s not actually powering off. It seems that the fans are still spinning, but I get a black screen and a non responsive computer.
 

keysofanxiety

macrumors G3
Nov 23, 2011
9,539
25,302
Ok update. It’s not actually powering off. It seems that the fans are still spinning, but I get a black screen and a non responsive computer.

Sounds like GPU. The fact it doesn't happen with the old GPU would further confirm this.
 

blackdbird

macrumors member
Feb 2, 2016
39
9
try to use this cable , hook it up from dvd drive and see if it goes away, i have the same problem with my 980ti hybrid but after using this cable i never came across random shutdown while underload


15pin_SATA_male_to_2x_8pin_6_2_PCI-E_Power_Supply_Cable_20cm-40cm_7_800x.jpg
 

MIKX

macrumors 68000
Dec 16, 2004
1,815
691
Japan
try to use this cable , hook it up from dvd drive and see if it goes away, i have the same problem with my 980ti hybrid but after using this cable i never came across random shutdown while underload


15pin_SATA_male_to_2x_8pin_6_2_PCI-E_Power_Supply_Cable_20cm-40cm_7_800x.jpg
No way ! It should be TWO MINI-6 pin to a SINGLE 8 pin to the GPU 8 pin socket.

This is the correct cable for the GPU 8 pin socket ( US$4 ) : https://www.aliexpress.com/item/Dua...8-Pin-Video-Card-Power-Cable/32822042322.html

The other cable is TWO SATA's to a SINGLE 6 pin ( if there is a 6 pin socket on the GPU ).

My efi'd @ 5.0GT/s Sapphire Dual-X 7970 3gb. is wired this way - works perfectly under heavy load.
 
Last edited:

thomasthegps

macrumors regular
Sep 23, 2015
220
145
France
Specs are
12 core 3.46ghz - 4,1 flashes to 5,1
Rx580 installed with two 6 pin to a dual 6 pin to 8 pin adapter.
48gb ram ddr3 ecc 1333

I’m getting consistent restarts when trying to render out 4k footage in premiere and AE. Takes a few minutes then it will turn off.

I thought it might be overheating, so installed Fan Control and ran the fans full blast. Temps seem ok but still get a hard shutdown.

Pulled the rx580, reinstalled the gt120 and the shutdown problem goes away. Obviously the render now takes way too long to be useable.

Brand new install of High Sierra.

Now I’m thinking maybe it’s the GPU or GPU cable. Any tests you can think of to help me narrow down the problem?

Thanks!

If you have a working pc lying around open the case and connect the GPU cables from the power supply to your GPU inside your mac pro. Turn on both computers at around the same time, redo your test and see if it still crashes. If it does power isn't the problem something else is wrong.
 

tsialex

Contributor
Jun 13, 2016
13,071
13,276
try to use this cable , hook it up from dvd drive and see if it goes away, i have the same problem with my 980ti hybrid but after using this cable i never came across random shutdown while underload


15pin_SATA_male_to_2x_8pin_6_2_PCI-E_Power_Supply_Cable_20cm-40cm_7_800x.jpg
This cable is trouble with any high-end GPU. SATA power only supply up to 54W. The GPU expects 150W from the 8-Pin connector and you can only supply 108W.
 
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