I don't know anything about pclab, however with a feud between a manufacturer and the site I doubt their credibility and their integrity.
Why is it that certain posters (not just you) cling to one foreign sites review which isn't even a major tech site such as AT, [H], Toms, Guru3D, TPU, TR, Bit-Tech, etc. etc. etc. Their results don't even line up with any other sites that I'm aware of. Who would even look twice unless you are or speak Polish? Perhaps there aren't good sites investigating it, but at least pick a credible site and not one allegedly in a conflict with a gpu manufacturer (I don't speak Polish so I don't know about the controversy surrounding the site, I'm just going off posters remarks here in AT).