CMP Randomly Sleeps, Won’t Wake...

[spetznatz]

A few months ago, my 4,1 (flashed to 5,1, running High Sierra 10.13.6) developed the above problem. It would sleep while I was actually using the mouse. Only restarting would get the machine running again, and it would stay up for about 30 minutes before sleeping again. I reset the NVRAM, did multiple SMC resets, re-installed the firmware... nothing worked.

However, I noticed that if I switched the monitors off (monitor sleep is a problem with my system) while the MP was still running, it wouldn’t sleep – I could leave it for days and it would keep running. So, I disconnected my secondary monitor and – hey presto! – no more sleep problems.

So, I swapped out my secondary monitor for a spare, and... the problem returned. So, I thought it must be the DVI port that the monitors were connected to. Secondary monitor then attached to the HDMI port on the graphics card (Radeon R9 280X, 3GB). The problem persisted. I tried it with an HP, Sun and Dell monitor as the secondary, on both the DVI and the HDMI ports. It seems that just the fact of having a secondary monitor attached is causing the problem.

So, I suppose a new graphics card is in order? Can't think of anything else it could be...

 

[bin90a]

I certainly had some problems with waking the cMP with High Sierra, and maybe before as well. The machine would sleep and was impossible to wake, I had to restart to get anything. However, when I upgraded to Mojave, including a new graphics card (at some expense ) the problem disappeared. No problem with waking or getting a response. So, the issue seemed to go away with the upgrade.

 

[startergo]

A few months ago, my 4,1 (flashed to 5,1, running High Sierra 10.13.6) developed the above problem. It would sleep while I was actually using the mouse. Only restarting would get the machine running again, and it would stay up for about 30 minutes before sleeping again. I reset the NVRAM, did multiple SMC resets, re-installed the firmware... nothing worked.

However, I noticed that if I switched the monitors off (monitor sleep is a problem with my system) while the MP was still running, it wouldn’t sleep – I could leave it for days and it would keep running. So, I disconnected my secondary monitor and – hey presto! – no more sleep problems.

So, I swapped out my secondary monitor for a spare, and... the problem returned. So, I thought it must be the DVI port that the monitors were connected to. Secondary monitor then attached to the HDMI port on the graphics card (Radeon R9 280X, 3GB). The problem persisted. I tried it with an HP, Sun and Dell monitor as the secondary, on both the DVI and the HDMI ports. It seems that just the fact of having a secondary monitor attached is causing the problem.

So, I suppose a new graphics card is in order? Can't think of anything else it could be...

It may be a sign of failing PSU. It started doing that on mine and when I replaced the PSU it disappeared. If you are buying it from eBay get the squaretrade warranty. Remember you will be buying a used same age PSU God knows when it is gonna fail.

 

[bin90a]

Just wanted to clarify that I never had problems early on, they just seemed to manifest with Sierra or High Sierra (can’t remember which)

 

[mateuszd]

I have a similar issue with my Mac Pro 5,1 with a Radeon R9 290x and Mojave.

Every now and then, after putting it to sleep, it won't wake up properly, in the better case, I press space every now and then and the screen turns on and in worse case, I have to either reconnect the DP cable. This makes me think that the issues are caused by Radeons, I'm going to try a GTX 680 when it arrived in a few days because a GTX 960 worked well before upgrading to Mojave when the Nvidia driver was installed. In my specific case, in addition to sleep issues, I have flickering of the screen issue after a cold boot too.

P.S: My first post, hello!

 

[spetznatz]

Thanks, all... PSU sounds like a good call. Mojave's not an option for me ATM, because I get the dreaded 'No Network Hardware' error after installing, and don’t have a 'sysctl,conf' file to delete!