Hi, i had same problem but i tested to record on other HDD when result with 3.8.0 is perfect, when i compare the hdd , one is 5400 RPM (many drop 60 to 30 fps) and the other is 7200RPM (60 fps constant)... don't know if that can help you.... I'm recording to an SSD, a Samsung 850 Evo, so that shoul...