Maximum frame rate for Multi-camera adapter v2.2


I have Multi-camera adapter v2.2 (UC475 Rev.C) on Raspberry pi 4b with two OV5647 cameras.
Everything is OK with C++ example you provide except for frame rate.
The printed frame rate from the example is around 10fps and 5fps for each camera.
I’d like to capture 640x480 images continually at least 15fps for each. Is it possible?