So the psu shroud isn't removable? There's no screws holding it in place?
In your current chassis, there's only one real source of air for the gpu - the rear PCIe slots, and... that's a pretty small area.
1)No.
2)No.
Because that chassis shares similarities in design with your current chassis.
Everyone's got their tastes, you like what you like... but what you like in a chassis - just going from 2 samples - gpu cooling is an afterthought.
Your going to have to take into account those subpar gpu thermals and build/compose with that in mind.
Closed off, or near closed off, front panel designs are the nemesis of axial fan cooled gaming graphics cards.
Psu shrouds and their proximity to axial fan cooled gpus - the closer it is, the worse it is - is right behind it.
Psu shrouds also block a potential source of air from below - there's ones with holes drilled in... Meh.
Liquid cooled and blower models do not suffer from these... 'oversights', as they excel in cooling in small spaces. The axial fan coolers need their space.
Let's see... EVGA 980Ti Classified...
TPU has 3 bios files for that on record...
WTH... 345w and 425w power limits?! If your card's Vbios has power limits like that... well no wonder you're having thermal issues... that's only part of the picture though.
It's just a dual axial fan cooler too... wow.
Right! Would the other 2 cards run cooler? Unfortunately, this is a yes and no answer.
Gpu core: Navi should be more power efficient than old Maxwell.
Vram: GDDR6 has higher operating temps than GDDR5. Even on custom gpu coolers, R5 can be kept cooled with just fans and no heatsinks on 'em. Can't do that with R6 memory; fans and heatsinks needed. Can't forget all that's on a shared heatsink too.
VRMs: Sapphire Pulse RX 5700XT has
recorded power limits of 180w and 195w.
Should have an easier time cooling the Navi gpu... just keep in mind the main source of air in your chassis for the gpu.