slow rx 5600 xt fps

[Javad Karabi]

given this setup:
laptop -thunderbolt-> razer core x -> xfx rx 5600 xt raw 2 -hdmi-> monitor
DRI_PRIME=1 glxgears gears gives me ~300fps

given this setup:
laptop -thunderbolt-> razer core x -> xfx rx 5600 xt raw 2
laptop -hdmi-> monitor

glx gears gives me ~1800fps

this doesnt make sense to me because i thought that having the monitor
plugged directly into the card should give best performance.

theres another really weird issue...

given setup 1, where the monitor is plugged in to the card:
when i close the laptop lid, my monitor is "active" and whatnot, and i
can "use it" in a sense

however, heres the weirdness:
the mouse cursor will move along the monitor perfectly smooth and
fine, but all the other updates to the screen are delayed by about 2
or 3 seconds.
that is to say, its as if the laptop is doing everything (e.g. if i
open a terminal, the terminal will open, but it will take 2 seconds
for me to see it)

its almost as if all the frames and everything are being drawn, and
the laptop is running fine and everything, but i simply just dont get
to see it on the monitor, except for one time every 2 seconds.

its hard to articulate, because its so bizarre. its not like, a "low
fps" per se, because the cursor is totally smooth. but its that
_everything else_ is only updated once every couple seconds.