These are the only decent gaming laptops I'm aware of:
https://www.msi.com/Laptops#?tag=GT-SeriesIf you browse thru the series categories, you'll find the bargains, they aren't always
on the first page.
There are a few other brands that run similar specs, some are cheaper,
but the MSI's ROCK !
Great cooling, latest tech, they are expensive-ish.
Laptops come with pre-set options that are difficult to upgrade, the MSI laptops are
upgradeable with pre-set options.
There is a large and confusing range of models, but one will offer good specs and a cheaper price,
it's a complex choice with MSI.
You can buy the bits and assemble a good PC for half that price,
and still have as good as or better performance than the MSI laptop.
With NVidia gaming cards, the second digit is the important one, or
was until recently as the numbers went thru 1000.
so.....the 60 series..... 460, 560, 660, 760, 860, 960, 1060 are the minimum decent gaming cards,
the 50 series doesn't hack it as far as I'm concerned.
CPU is important, GPU is important. You aim for matched (max) performance.
The general deal when you buy a pre-built is that you almost always get nasty
surprises later on after purchase, with components chosen for cost, not functionality.
Custom made and you can pretty much do whatever you like with it if you get good
core components.
The last couple of links you gave look like good specs, but you start looking at
hard drive speed and capacity, whether that particular video card is bottlenecked etc.
The devil is in the detail, and it takes a bit of research into these products to really
understand exactly what you are getting.
My main concern is a good motherboard personally, but if everything you buy is
good quality, you'll be very happy with it.
If you look at the MSI laptops, they are all ready to go, with good components,
large screens, adequate cooling (important with a laptop) and expansion capability,
so, they are a good option, but quite a bit more money.