@CptLucky8 - I would be wary of relying on the in-game stats as a proxy for what is actually being displayed in headset. Instead, I would suggest looking at SteamVR’s performance graphs.
Here are two captures from the same session using the current beta and that temp linux build.
With SteamVR v1.15.16:
With SteamVR v1.14.16:
What you’re looking for is nice flat lines which correspond to smooth displayed frame intervals.
In the GPU section of the Frame Timing graph, there is a white line labeled “Present (count)”. This corresponds to the perceived framerate. A value of 3 = 1/3rd framerate, so at 90Hz, this means running at a steady 30 fps, which is what we see in the first image above running the latest version of SteamVR.
On the second image, this value is bouncing between 2 and 3, meaning that the framerate is fluctuating between 30 fps and 45 fps (each image from the sim is being displayed sometimes twice, sometimes three times). Framerate on average is better, but also choppier.
Additionally, there is a green line labeled “First Viewed”. You’ll note that this is fluctuating between 3 and 4 which indicates that there is an extra frame of latency between the sim and display using this version of SteamVR. In the top image, that green line is sitting right above the cyan “Ready For Use” line staying steady at 3.
You may also notice the mini perf graph at the bottom of the SteamVR desktop widget. This is showing what we’ve already seen in Frame Time graph: Red = 1/3rd framerate, Yellow = 1/2 framerate. In the top image we are pretty much solid red, while in the bottom we are fluctuating a bunch. Both of these graphs can be displayed in headset. The Frame Timing graph has a checkbox, and then shows up on the back of your controller, while the mini graph has an option to enable in SteamVR Settings > Developer.