I tried many version of windows 10, all are heavy for old computer, but I have small tablet like laptop with win 10 home which is very light and smooth, I tried the to install same version on faster old desktop but it's heavy.
how they tweak it to became smooth?

What's the spec of your tablet?

I've a lenovo miix 8, with intel atom, 2gb ram. Upgraded it to win 10 long time back. It's quite ok, unfortunately the touchscreen stopped working, so I can't use it anymore.

what is the hardware spec?
most likely ur laptop is running on faster harddisk.