Why UE fix FRenderingThreadTickHeartbeat sleep(6.25ms), and FMediaTicker sleep(5ms)

Development Rendering
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1

I tried to modify the heartbeat and media playback sleep times so that they only sleep once per frame, but this didn’t seem to be a problem. Is there any other effect if I adjust to double or based on frame rate? What UE is set to 5ms and 6.25ms by default?

uint32 FMediaTicker::Run()
{
	while (!Stopping)
	{
		if (WakeupEvent->Wait(FTimespan::MaxValue()))
		{
			TickTickables();
			FPlatformProcess::Sleep(0.005f);
		}
	}

	return 0;
}

 /* Maximum rate the rendering thread will tick tickables when idle (in Hz)
  float GRenderingThreadMaxIdleTickFrequency = 40.f;
  1.0f/160 = 6.25ms
*/
virtual uint32 Run(void)
	{
		while(GRunRenderingThreadHeartbeat)
		{
			FPlatformProcess::Sleep(1.0f /(4.0f * GRenderingThreadMaxIdleTickFrequency));
			if (!GIsRenderingThreadSuspended && OutstandingHeartbeats.GetValue() < 4)
			{
				OutstandingHeartbeats.Increment();
				ENQUEUE_UNIQUE_RENDER_COMMAND(
					HeartbeatTickTickables,
				{
					OutstandingHeartbeats.Decrement();
					// make sure that rendering thread tickables get a chance to tick, even if the render thread is starving
					if (!GIsRenderingThreadSuspended)
					{
						TickRenderingTickables();
					}
				});
			}
		}
		return 0;
	}