weird gpu power consumption

[Tiwaz]

So I noticed that even under a constant core clock and constant usage, there are a lot of fluctuations in power consumption, how is this possible ? Or is it just a MSI Afterburner bug? I made two vertical lines where the clock and usage are pretty consistent and the gpu power fluctuates a lot. GPu is a Aorus gtx 1080 ti

 

thanks for the help,

Tiwaz

 

 

 

[Mira Yurizaki]

If GPU utilization is like CPU utilization, it's only an indication of the percentage of time the GPU was not in any sort of idling state, not how much of the total resources are in use. Some things could idle or not draw much current because they're not doing anything.

 

So for example, if you have an SM using all 4 of its shader groups, it may count as being 100% utilized even if maybe only 50% of the shaders were needed for the task.

[Tiwaz]

27 minutes ago, M.Yurizaki said:

If GPU utilization is like CPU utilization, it's only an indication of the percentage of time the GPU was not in any sort of idling state, not how much of the total resources are in use. Some things could idle or not draw much current because they're not doing anything.

 

So for example, if you have an SM using all 4 of its shader groups, it may count as being 100% utilized even if maybe only 50% of the shaders were needed for the task.

but then the power consumption should also be maxed out at  90-100%

[Mira Yurizaki]

17 minutes ago, Tiwaz said:

but then the power consumption should also be maxed out at  90-100%

If the SM can gate 50% of its execution units then no, it should be much lower. Each SM looks like this:

 

100% power utilization means that everything is doing something. GPU utilization may only mean that each warp scheduler has something to do, but that does not mean every compute unit has something to do.

 

As a simple sanity test, I made a Python script that increments a variable in a forever loop. CPU usage shoots up to 13% even though this operation should only take one execution port out of the 6 or 7 execution ports a CPU core has.

[Tiwaz]

9 minutes ago, M.Yurizaki said:

 

so there is nothing wrong with my gpu and it runs at the correct clocks as shown in msi afterburner?