Reproduction steps:

1. Open "CommandBuffers.zip" project
2. Build & Run for Android
3. Open the Profiler
4. "Toggle Camera"
5. Notice the "CPU Usage" (Gfx.WaitForPresent)
6. "Toggle [Command Buffers: OFF]'
7. Notice the "CPU Usage" spike (Gfx.WaitForPresent)

Expected Result: Similar/better performance without Command Buffers
Actual Result: Worse performance without Command Buffers

Reproduced with: 2019.3.0a8, 2019.2.0b8, 2019.1.8f1, 2018.4.3f1, 2018.3.14f1, 2017.4.29f1

Note:
Repro with OpenGLES3 and Vulkan; Mono and IL2CPP (OpenGLES2 doesn't render at all)

Repro Devices:
VLNQA00012, Samsung Galaxy S6 (SM-G920F), Android 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760
VLNQA00013, Samsung Galaxy S6 edge+ (SM-G928F), Android 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760
VLNQA00005, Samsung Galaxy S7 (SM-G930V), Android 7.0, CPU: Snapdragon 820 MSM8996, GPU: Adreno (TM) 530
VLNQA00093, Samsung Galaxy S6 edge (SM-G925F), Android 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760
VLNQA00224, Samsung Galaxy A5(2017) (SM-A520F), Android 8.0.0, CPU: Exynos 7 Octa 7880, GPU: Mali-T830
VLNQA00017, Huawei Nexus 6P (Nexus 6P), Android 8.0.0, CPU: Snapdragon 810 MSM8994, GPU: Adreno (TM) 430
VLNQA00166, Huawei P20 (EML-L29), Android 8.1.0, CPU: HiSilicon Kirin 970, GPU: Mali-G72
VLNQA00138, Huawei P20 Pro (CLT-L29), Android 8.1.0, CPU: HiSilicon Kirin 970, GPU: Mali-G72
VLNQA00217, Razer Phone 2 (Phone 2), Android 9, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630
VLNQA00109, Xiaomi MI NOTE Pro (MI NOTE Pro), Android 7.0, CPU: Snapdragon 810 MSM8994, GPU: Adreno (TM) 430

No Repro Devices:
VLNQA00002, Samsung Galaxy S5 Neo (SM-G903F), Android 6.0.1, CPU: Exynos 7 Octa 7580, GPU: Mali-T720
VLNQA00015, Samsung Galaxy Note8 (SM-N950W), Android 8.0.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540
VLNQA00263, Google Pixel 3 (Pixel 3), Android 9, CPU: Snapdragon 845, GPU: Adreno (TM) 630
VLNQA00155, Meizu PRO 7 Plus (PRO 7 Plus), Android 7.0, CPU: MediaTek Helio X30 MT6799, GPU: PowerVR Rogue GT7400 Plus