Wierd GPU problem?

[undercooked spaghetti]

Hi all, I have noticed that if i disable my CPU's onboard integrated GPU, my in-game FPS takes a hit regardless of the fact that i have a dedicated GPU running all my games. Doesn't matter where i disable my iGPU from (device manager or the BIOS), it still causes this problem. YES MY DISPLAY CABLE IS PLUGGED INTO MY GPU AND NOT IN MY MOTHERBOARD. So after some performance monitoring, i found out that my dedicated GPU's utilization drops if i disable my iGPU. Such as when playing RDR2, i get around 95%-98% utlization and 60-70 FPS on average. After i disabled my iGPU, my utlization dropped to 60%-70% and my FPS to 40-48. I have asked this question on different forums and no one could tell why this is happening. This happens in other games as well. Almost as if the iGPU was running in SLI lol. I disabled it in the first place because i had a few GPU driver/registering issues with a few softwares. Now i have re-enabled it but I'm still curious why this happens. Is it the windows? the GPU drivers? my motherboard? My GPU BIOS?. I'm considering to upgrade to a Ryzen soon and there will be no iGPUs to help me there. What sorcery is this?\

 

PC Specs: i7-4790 cooled by Cooler Master MA410p, 16GB DDR3 1600mhz, MSI Gaming X GTX 1070, 240GB GIGABYTE SSD (boot), 2TB WD Blue HDD (Games), CORSAIR HX620 PSU

 

 

[SupaKomputa]

you can manually assign the games to use the gpu.