Is there a limit to frames per second for a composite usb video capture device?

edit

I ran a code which seems to have increased my frame rates from about 25fps to about 60fps, but I am not sure if I am getting true 60FPS. I feel I may be getting 60fps per second, but many of those frames are possible repeats? I am using an Elgato Video Capture device which uses USB and composite video on Windows 10.

from imutils.video import WebcamVideoStream
import imutils
import cv2
import time

# normalFPS = cv2.VideoCapture(0)

# This replaces cv2.VideoCapture(0)
fastFPS = WebcamVideoStream(src=0).start()

while True:
    timea = time.time()

    # _, normalFrame = normalFPS.read()

    # This replaces ret, frame = cap.read()
    fastFrame = fastFPS.read()

    # cv2.imshow('normalFrame', normalFrame)

    cv2.imshow('fastFrame', fastFrame)
    key = cv2.waitKey(1) & 0xFF
    timeb = time.time()
    Latency = (timeb - timea)
    print("Latency: ", Latency * 1000, "ms")
    print("FPS: ", 1 / Latency)

    if cv2.waitKey(25) & 0xFF == ord('q'):
        break

# fastFPS.release()

cv2.destroyAllWindows()
fastFPS.stop()