Just bought a cool Dell Venue 11 Pro 7140 but has Poor Passive Cooling. Possible to Upgrade?

[Dimondminer11]

So as the title says I just got a Dell Venue 11 Pro 7140 with the core m 5y71 and dell, for cooling, just slapped a tiny piece of copper ontop of the cpu and called it a day. I'd like to make that better and at the very least give it more thermal mass to soak up heat as it very quickly thermal throttles and drops core frequencies down to the 1.6-1.7Ghz range at 100% load. Any suggestions?

Edit: And I should mention that affects GPU clocks as well when it thermal throttles. And because of this chip being what it is it is able to hit 2.6GHz on both cores given the thermal headroom