With a little less saturation, 'cause I think it was eyeburning.

Before:


After:

I searched for some wooden floor tiles and now I see how they do it. I'm gonna try to do some too.

I feel like it's so tiring graining the boards, because the tile will have at the end 256 collors :s

Looking much better. You'll want a few versions of the tiles or you'll find a very repetitive pattern. I'd lower the saturation a bit too.

You don't need to pre-zoom. The forum has a zoom feature, click on any image to zoom in, ctrl+click (and I guess cmd+click on Macs?) to zoom out.

I have never seen a wooden floor that was staggered width-wise rather than length-wise. Compare the tile you didn't make and how the planks are arranged with yours. That tile has a much more common arrangement.

You have a large soft shadow at the edge of your bits of wood. How is that shadow being created, what's blocking the light?

Also, I recommend not starting with a big messy bunch of noise like you did here. Get in there with the pencil took and try to depict wooden texture with a limited palette. That way, you'll need to look at the larger-scale features of wood (look at actual wood for reference! not other people's interpretations of it) instead of hoping that something messy will look like wood.
That said, I think you had some good ideas with this latest tiles as far as texture is concerned. They're just getting lost in the nonsense shadow and the noisiness of the texture.

It looks more like bricks or tiling on a roof. i think the planks should be longer than they are wide.

Thank you, guys! It's gonna help me a lot.
I'm gonna make some more tests and post it here when it's done.