When i put 6700K into optiplex 7040 sff and turn on torture test in prime95, i can read parameters in cpu-z:
frequency: +-3,4GHz
power: +-65W
+-4GHz if only 1 core is under load
These values are same/typical for 6700 non-k (6700 has a base clock 4GHz, 4,2 Turbo and 91tdp). I think that mobo in 7040 sff is choked to 65W TDP and i wonder if this limit can be increased trough bios editing.

I`m totaly aware of treats like a mobo blow up. Sky is the limit c:

You can set these in UEFI or in the OS itself. Try Intel XTU so see which values work before changing them in UEFI or mod your BIOS.

"Curret/EDP limit thtottling" in xtu has yellow color and displays YES, so i think there is nothing to do in xtu :/

BUT, actualy yes... idk how to send picture here, but i`ve undervolted my cpu (-0,17) and increased current. Now i`m able to reach @3,98 all core in prime.
So, thank you very much stovorsen :)

You're welcome! The available options in XTU differ per cpu generation. Smart move to undervolt to lower temps enough to run at max speed. Easier than replacing thermal paste or install a new cooler too haha.