i recently purchased a surface 3 4gb ram 128gb drive, non-LTE. i bought the 4gb ram version because i felt it would help the response and speed. what i immediately found was there was an immediate lag in the response of the touch using any application. slow to the point of thinking "did that input, take?" i got to the point where i waited figuring the interface would respond in a few seconds. and it typically did. but it is a very annoying lag that isn't acceptable to any user. i am getting ready to purchase the LTE version so I am very glad to hear that your replacement fixed the problem and if I come across this again, I'll ask the Microsoft folks to check it out. thanks again.