No it isn't. I encourage you to go watch the Jayz2cents video where he goes over bottlenecking. He actually has 2, with one being an AMD chip against an Intel chip. there was a 2 frame difference in GPU heavy games and a 5 fps drop in CPU heavy games. I recently upgraded to an RX 480 and NEVER drop below 60 frames at Ultra settings in BF1. I have a 60mHz panel so I have the fps limiter set at 60. Also, a motherboard shouldn't bottleneck you. The only differences between a cheap mobo and expensive one are overclocking ability, part quality, lan speed, audio quality, pci-e slots, ram slots, sata slots, and usb slots. None of those have anything to do with framerate
the motherboard bottlenecks cause my motherboard is a pcie 2.0 and gpu is a 3.0 so that has to take the fps down a little bit
ahh... Didn't know those things still existed.