You can always choose alternatives such as Toshiba's or Seagate's hybrid SSHD or WD black square HDD+SSD dual drive.
Or go for an expensive 500gb/1tb samsung 840 evo.

And well, the lack of msata/NGFF factor in local set Y510p is still making me hesitate for it.
Maybe will wait for next Y series instead lol and hope there'll be ngff connector in it.

Sry, newbie here
Recently, I bought Y510p (755m) and ask the seller if possible remove the dvd drive and add another card to make it sli.. He said it is not possible because non-hotswappable..Hmm, I'm interested to buy another card in future
Did the seller gives wrong info or it is true?

might be that the game detected that due to 2 GPU, it chooses to use intel's version.
try using nvidia control panel and set the 3d to nvidia instead of auto select.
if not you can try to fresh install the whole driver.
currently is 332.21..
dude instead of just giving non helping one liner try to give a better suggestion.
just saying.

lag issue and low memory are different.
lag issue could be causd by the gpu problem i mentioned.
you may try and set the programs that will run using gpu under programs in nvidia control panel.
(i'll include screenshot later as right now im using office laptop)
for low memory issue, as mentioned in the link, could be memory leak problem.
you can try the solution from here.

http://www.eightforums.com/performance-mai...nt-leaks-5.html