Question GPU can not pass 70% when CPU is at 100%

[cprdf89e]

Here's my spec:

CPU: i7 7700k
GPU: EVGA GTX 1080 SC
MB: ASUS Z270-A
PSU: EVGA 550W GD
used for 3 years

So recently I was playing games and notice sudden drops of fps. I use Afterburner and notice that when my CPU usage reaches certain numbers, my GPU usage will drop from 9x% to 70%.

Afterward, I try testing with Furmark and notice that my GPU usage cant pass 70% when my CPU is at 100%.

here are some screenshots

CPU 100%

https://imgur.com/a/Q4B6IQt

View: https://imgur.com/a/Q4B6IQt


CPU 0%

https://imgur.com/a/doQng5D

View: https://imgur.com/a/doQng5D


I test the same card on another PC (9400F) and has no problem at all.

Is it because my PSU has not enough wattage, or it is just bottleneck?

 

[rgd1101]

bottleneck