It is still a very capable quadcore, it is skylake, If you need the extra threads from an i7 then go with it, that laptop will have no issues running Elite Dangerous
Install adblock
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keep in mind the owner of the video gets NO MONEY from your view, So if you want to support content creaters disable the addon
the 950 pro is an m.2 SSD. Your laptop doesn't have that slot. And they're showing that the SSD is so fast it gets so hot and thermal throttles time to time, even if your laptop has the slot it wouldn't be a good idea to use that SSD
You probably can't upgrade the CPU. Most CPU's on laptops (even more on the lower on such as the i3) are soldered on the board. Even if you were extremely lucky and it was a socketed CPU as you know laptop cooling isn't good and a more powerful CPU would heat it up more and it probably couldn't...
Download a tool such as seagates "Seatools" and do a test to see if your hard drive is bad. Don't go get a diagnostic. A new hard drive would cost less then $100. That laptop probably still has warrenty on the hard drive