What type of cooling can we expect. Dell & Apple and many other manufacturers have failed to provide adequate cooling at the cost of CPU throttling when things run hot. Especially these days with thin laptops with 3 main heat sources inside being CPU GPU & battery (Charging & Discharging).
Apple failed even with aluminium chassis & cases. Dell dropped the ball with the Latitude e6540 Quad Core i7 with AMD Graphics they simply melted down. To many manufactures simply use the same cooling solution for an i7 rig. Using the same heat pipes & fan as they use for the i3 & i5 siblings.
If you want to use these for full on Gaming or Rendering you need 3rd party cooling to make sure you don't cook your new expensive rig.
I would think that in a laptop environment that a 6 core processor will offer equivalent performance or better as it would not throttle as soon as an 8 core would & even when it does throttle it won't throttle as low. Most tasks performed on a laptop would benefit more from extra clock speed than extra cores.