Unplug power cable to ML GPU while workstation is on.

[Robert222]

I have two GPUs and one is strictly used for ML, its a Tesla M40. My question is if I disable the GPU in device manager and then unplug the power cable will that cause a problem?

[emosun]

Yeah it won't function

it's going to want some form of electricity and software for it to do it's thing

[manikyath]

i wouldnt risk it. best case it works, second best case it crashes your system, worst case something breaks as a result.

[Robert222]

10 minutes ago, manikyath said:

i wouldnt risk it. best case it works, second best case it crashes your system, worst case something breaks as a result.

Well I have booted up with the ML GPU unpowered and everything worked fine. So, I'm just wondering what is the difference between booting with the ML GPU powered off and turning the ML GPU off while the workstation is on?

[BobVonBob]

I can basically guarantee it will lead to a hard lock up, even if you disable it first. I assume you're trying to do this to save power, but you might as well make any changes with the computer shut down, because trying to mess with PCIe devices with the computer running will shut it down anyway.

[manikyath]

1 minute ago, Robert222 said:

Well I have booted up with the ML GPU unpowered and everything worked fine. So, I'm just wondering what is the difference between booting with the ML GPU powered off and turning the ML GPU off while the workstation is on?

it's not because you disable it in windows, that the device is not running.

 

powering it up with some rails missing (which is what happens when you power it without pcie power to the GPU) will probably make the GPU fail to init, and keep it at that. when you unplug it, the GPU is already initialized, and at least doing mundane stuff like DRAM refresh cycles.

 

it's basicly like the difference between yanking your power cord while your pc is in the bios, and yanking the cord while it's in windows.

it doesnt mean something will break, it's just that there's now a lot more factors to consider.

 

it's your hardware, do with it what you want, experiment away, but i wouldnt want to risk bricking a pricy card.

[Robert222]

20 minutes ago, manikyath said:

it's not because you disable it in windows, that the device is not running.

 

powering it up with some rails missing (which is what happens when you power it without pcie power to the GPU) will probably make the GPU fail to init, and keep it at that. when you unplug it, the GPU is already initialized, and at least doing mundane stuff like DRAM refresh cycles.

 

it's basicly like the difference between yanking your power cord while your pc is in the bios, and yanking the cord while it's in windows.

it doesnt mean something will break, it's just that there's now a lot more factors to consider.

 

it's your hardware, do with it what you want, experiment away, but i wouldnt want to risk bricking a pricy card.

OK, I know that it's running but I thought because you can't monitor statuses on the GPU that it wasn't doing anything. I mean when the GPU is idle (this is ML only GPU) the GPU Chip power is zero.

[Robert222]

OK, I tired it, literally disabled the GPU in device manager and then unplugged the power cable...Nothing happened to the workstation after unplugging the ML GPU, but when plugging the GPU power cable back in the card and enabling it the device manager displayed a warning, I then rescanned for new devices and the GPU card no longer showed up. I had to reboot to bring the card back online. The card worked, so no damage at least...BTW the M40 cost me $100, so it wasn't such a costly card. 

[da na]

2 minutes ago, Robert222 said:

OK, I tired it, literally disabled the GPU in device manager and then unplugged the power cable...Nothing happened to the workstation after unplugging the ML GPU, but when plugging the GPU power cable back in the card and enabling it the device manager displayed a warning, I then rescanned for new devices and the GPU card no longer showed up. I had to reboot to bring the card back online. The card worked, so no damage at least...BTW the M40 cost me $100, so it wasn't such a costly card. 

*advised not to*

*does it anyway*

 

It worked this time but I really don't recommend this. Could cause PSU damage, GPU damage, motherboard damage, OS corruption... 

[Robert222]

2 minutes ago, Mel0nMan said:

*advised not to*

*does it anyway*

 

It worked this time but I really don't recommend this. Could cause PSU damage, GPU damage, motherboard damage, OS corruption... 

Understood, the PSU is pretty robust and has resettable circuit breakers for all outputs, so PSU damage not likely. Because the Chip power is zero when it's not operating I kinda guessed that any PCIe com wasn't happening, so only local to the GPU board stuff was gong on. But you're right damage to the GPU board was possible.