For the most part, the HQ is far better than the U for video editing because the U processors generally have only two physical CPU cores while the HQ processors are true quad-core CPUs. And no dual-core CPU, regardless of how high it's clocked at, is as powerful (performance-wise) as even a mediocre quad-core CPU.
And on top of those differences, the "stock" (base, non-turbo) clock speed of the U processors is typically significantly lower than those of the HQ processors, instead relying on relatively high turbo boosts.
Starting this year with the forthcoming Kaby Lake Refresh mobile CPUs, the U processors will begin to feature true quad-core CPUs. However, their base clock speeds will continue to be significantly lower than their HQ siblings.
Ok this thing i know it more or less. Someone told me that the real difference is when rendering, that you don't notice much during common operation
is that correct?
The real difference is in the rendering and exporting. The real-world exports will take at least 1.5 to 2 times longer with a U than with an HQ of otherwise similar specs. And depending on your particular laptop, the battery may peter out in the middle of an exporting job with a U processor. This is exactly why we recommend exporting video with the laptop connected to an AC mains outlet, not off of battery power.
ok that is really clear
any laptop suggestion?of course the less expensive and preferably the less big in size