I also just bought Kingston A400 and i used it for my OS. I noticed a very annoying issue with it. more often than not, my screen will freeze(unresponsive) along with the mouse cursor sometimes being able to move and sometimes not being able (stuck) but sounds are still being played without a problem during those unresponsive moments. Especially when programs are being opened.

Damn bloody annoying and it only happened right after i switched to A400 SSD. reformatted it and still the same shit.

does that have to do with the SSD not having DRAM cache?

What is your use rate? In terms of GB write/rewrite each month?
Did you usually keep it over 80% full?