Question why is my GPU spiking?

[Turnedlight]

Hi this is my setup-
I7-8700k 6-core 3.7GHz (currently overclocked to 4.2 of 4.7 GHz),
Asrock z370 pro4-IB
16GB of DDR4- 2666Mhz memory.
240 GB SSD and 1TB HDD
Zotac Nvidia Geforce RTX 2070 8GB
Windows 10. the CPU is liquid cooled on top of that i have 1 fan ( not counting the ones on the gpu and power supply) im consistantly getting 120+ fps but about every 10-20 seconds my fps dropss to 70-80 for a split second before shooting back up and repeating the process. After monitoring everything in the task manager i noticed its the gpu that keeps spiking up and down at the time the frames drop. what could be causing this? And how can i remedy this? its driving me mad. ive already uninstalled and reinstalled all my drivers.

 

[Metal Messiah.]

Make and model number of your Power supply unit/PSU ? What's the GPU and CPU temp value while gaming ?

 

[Turnedlight]

its a thermaltake smart series 600w. im not sure on model number but it says 80 plus gold on it. and i used to monitor the temps with CAM everything was well under normal temps. i cant rememeber what those were off the top of my head tho. The PC was built by IBUYPOWER a year ago. its the "Trace 9220"

 

[Turnedlight]

Make and model number of your Power supply unit/PSU ? What's the GPU and CPU temp value while gaming ?

Any suggestions? also i have a buzzing sound coming from the front of the case. ive taped all the wires down in that are but the buzzing persists in 2-3 second intervals. could this be my hardware? also noticed i didnt "reply" to you earlier so the info you needed is above

 

[Metal Messiah.]

Are you sure the buzz sound is not coming from your PSU itself ?

 

[Turnedlight]

Are you sure the buzz sound is not coming from your PSU itself ?

yes the PSU is on the opposite end altogether.