Frame Drops in Playback View from 20 to 90

Hello Community,

i have a big Problem with Framedrops during Playback View in Adobe Premiere. Its always start from 20 to 90 fps drops by frameindicator. And it feels like mirco stops during the playback it doesnt matter wich quality (Full, 1/2, 1/4)

Maybe its a Hardware Problem? Threadripper in combination with the ASUS GTX 1080 TI IOG? ( But all Benchmark test and stress test works very well)

Software Problem?

Kamera File Problem? Project Settings?

120 FPS Sony 7R III Files

Thank you for your help
Alexander Schroer

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AMD Ryzen TR 1950X WOF 16 x 3,4 Mhz

Asus ROG STRIX X399-E GAMING X399

Asus ROG Strix  GeForce GTX 1080 Ti 1GB OC Aktiv PCIe 3.0 x16

G.Skill Flare X Series schwarz, DDR4-3200 for Threadripper 1950X, CL14 - 32 GB Quad-Kit

SSD 500GB 1.8/3.2G 960 EVO PCIe M.2 SAM

be quiet! Dark Base 900  Big Tower

750 Watt be quiet! Dark Power Pro 11 Modular 80+ Platinum

Enermax LiqTech TR4 360 Watercooling - 360 mm

LG 34UM88C-P 34 Zoll Monitor 60 HZ IPS 3.440 x 1.440 Pixe