Copied Werewolf_fs layout here so thanks Werewolf_fs.     
DCS BETA 2.5.5 = 45 (60*) FPS (SSD drive) 
DCS Stable 2.5.4 = 45 FPS        (Normal 7200rpm disk drive)   
ASW OFF using Occulus tray tool.   
* If I touched nothing and ran the test straight and level both were 45 FPS. If I quickly raised the nose 45 degrees so that frame rate started to rise then leveled off (after a second or so into the run)both frame rates went up to 90ish but then in level flight may be 200 ft gained Beta settled at 60 FPS while the stable settled back at 45 FPS.      
System Specs:   
i7 6850K @ 3.6 Hgz 
ASUS ROG Strix X99 
32GB RAM 2133 DDR4 
Zotac Nvidia RTX1080  
480Gb HyperxSavage SSD  
Windows 10 PRO 1803 OS 17134.829 
Process Lasso =High Performance   
Graphics settings same for both:-   
TEXTURES: HIGH  
TERRAIN TEXTURES: HIGH 
C.TRAFFIC: OFF 
WATER: HIGH 
VISB. RANGE: HIGH 
HEAT BLUR: LOW 
SHADOWS: FLAT ONLY 
RES. OF COCKPIT DISPLAY: 1024 
MSAA: OFF 
DOF: OFF 
LENS EFFECTS: FLARE 
MOTION BLUR: OFF 
SSAA: OFF 
CLUTTER: 690 
TREES: 71% 
PRELOAD RADIUS: 100% 
CHIMNEY SMOKE: 2 
GAMMA: 2.1 
ANISOTROPIC: 16X 
TERRAIN OBJETS SHADOWS: FLAT 
COCKPIT ILUMINATION: OFF 
RAIN DROPLETS: OFF   
VR SETTINGS:   
PD: 1.5 
No hand controllers   
VR HARDWARE:   
OCULUS RIFT CV1 with oculus software ver. 1.38.256587 Firmware 709 
NVIDIA DRIVERS V 430.86