Question New build. parts are working separately, but not together.

Aug 6, 2020
i have modded before but haven't done a full build.
new pc parts list:

x570 taichi,
rx5700xt red devil,
ryzen 7 3700x and stock cooler,
Thermaltake ToughPower 750W gold,
coursair vengeance rgb pro 3200 16g ,
WD black 1tb nvme (from previous pc).

as far as i know everything is directly compatible. putting all the above parts together with gpu in top pci lane is not posting. moving gpu to the second lane gets me a unstable, slow, and choppy post that eventually crashes to a blue screen. removing the red devil and replacing it with my old rx580 in any lane gives a good boot, and runs without problem. i put the red devil in my old computer and it runs fine, but i ordered a replacement anyways. the new red devil preformed the same as the first in each computer( works in the old but not the new ), so im guessing its not the card itself.

I removed the nvme and replaced with a new wd ssd in sata and loaded fresh windows10 and fresh amd drivers. no post with red devil, full boot from rx580. Removed ssd completely and tried to post. No post from red devil, post from rx580. the mobo is at bios 3.2, so there shouldn't be any compatibility issues with cpu. installed everything (except new mobo and cpu) on old motherboard with old cpu and all the parts worked fine.
So its something between mobo, cpu, ram, psu, and gpu?… doesn’t seem like software is an issue. im stumped, help!