Reproduction steps:
1. Open the project attached by the user
2. Build and run the "SampleScene" (File -> Build and Run)
3. Set "Max queued frames" field to 1
4. Observe the FPS
5. Click on the "fs" button
6. Observe the FPS

Expected result: Frame rate in 2020.2 isn't lower compared to 2020.1.
Actual result: Frame rate is 2020.2 is much lower than 2020.1:

2019.4.15f1 ~1700 vs ~500 (at first it's 2000 in fullscreen, but after a bit it drops)
2020.1.14f1 ~2000 vs ~600 (same as with 2019.4.15f1, it first starts at 2000, then drops to 1700)
2020.2.0b12 ~1200 vs ~250 (the difference seems stable, unlike previous streams)

Notes:
- Not reproducible with DX12, Vulkan (the FPS doesn't drop after switching)