I don't get why this happens but it seems to happen a lot...
the OP said he wanted to get a new laptop. TO me that means he already knows the pros and cons, but decided he wants one. Maybe he wants to use it on the go, maybe he migrates between school/home/work and needs the portability. Some people dont have the ability or see the rational to spend more money on a good laptop and a good desktop, when the former does everything they need and they dont need to buy two things.
I don't get why someone who asks about a laptop is told "buy a desktop you will be happier"
Its like someone wanting a honda fit/jazz going to the dealership and they try and sell them a Chevy suburban.
The myth( i call it one) about laptops not being easy to service is hogwash. What he is looking at is a msi shared chassis, with prostar sager and clevo most likely. Meaning its a modular laptop.
The GTX980m is to the best of my knowledge only on a daughter card, and can be replaced by removing only two screws holding it to the mother board.
Most laptops of that size and caliber use standard mobile sockets for the CPU, and separate daughter boards for all the highly used IO ports. Its going to use a two or more fan cooling system and should never get that hot.
Also as far as not being fast as someone mentioned :some mobile processors top 20 fastest CPU's right now for the home when using shipping clock rates based on raw number crunching like geek bench. I can load up multi hundred megabyte systems in Solidworks and freely rotate them around in real time with no issues. i can play poorly coded games like skyrim and crysis 3 with no issues either, though both are not very "cutting edge" anymore they do tax your system more than something a little better coded.
Yes, if you want to sit there and try to play the newest greatest most taxing (and often just poorly coded games out there) then a laptop is not going to work. But if you want to do spreadsheets, movies, internet, and occasionally play some games, there is nothing wrong with them.
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i would also like to note that my laptop was in no way 4 k. It was less than the one the OP is looking at. A precision M4800 with 9cell 11 hour run time battery, same CPU, 8GB of 1866mhz ram, and the 2GB AMD Firepro m5100. You do not have to spend a fortune to get an upgradable, serviceable, professional quality notebook.