>
> Hello everyone,
>
> I am a little bit confused here... can somebody confirm that...
>
>         - on a pic16c84/04 one instruction takes 1us
>         - on a pic16c84/10 one instruction takes 400ns

That's correct. Timing is 4/fOSC in microseconds when fOSC is in Mhz.
4/4Mhz = 1 uS
4/10Mhz = 0.4 uS = 400 nS

>
> Of course, that does not include branches such as goto, etc..
>
> Please tell if I'm wrong, thank you!

You are correct.

BAJ