Lenovo said it only supports 8GB, in fact, 8*2 is ok (at least i5 U), but it's a bit lucky to try.

I'm Kingston D3 1600 8G*2. I tried it for a long time, changed it and restarted it.

The estimation of i3 is impossible, because the stripes of 8G are all 1600, and i3 is at most 1333.

In fact, in general, 8GB is enough ~

X60/x200t/x201i3323k9c/t400/t42/t23 pass by ~