The 3 pin is for ARGB to your motherboard..
What is your CPU and your PSU?
Are you using displayport or HDMI?
AMD Ryzen 7 3700x, Asus Tuf Gaming RX 6700 XT, Asus TUF Gaming x570 Plus, 32gb G.Skill TZ neo 3600mhz, Samsung 980pro 1tb NVME, Samsung 970 EVO Plus 1tb NVME, Lian Li Galahad AIO 240mm, Antec Titanium 1kw.