The only important lines for what interests us are :
2nd generation 2.3GHz Intel® Core™ i3-2350M processor, 6GB DDR3 SDRAM
Intel HD graphics 3000
640GB 5400RPM hard drive
Well, this isn't a "great" computer. I think it'll be alright for Technic if you can tweak the settings properly, since I've seen it run well on far shittier hardware.
But I'm not sure about Day Z.
Intel Core i3 isn't extraordinarily recent, but 6 GB of RAM is satisfying, I guess, since many very good PC's don'T have more than 8GB.
The most worrying is the Intel graphics 3000 video card. This is an integrated video card, IE a bad one. It may even handicap the gameplay for Technic. I think he should at the very least try to have a real video card if he wants to play video games with this computer. Also, the hard drive is perfectly satisfying depending on the price, 640GB should be plenty.
Two questions, what precisely is this computer? (Brand, code)
And how much is he paying for it? For 600 bucks, there's definitely more advantageous.
Edit :
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CHEEESYYY AS HELLLLL.