Well finally today I've updated my bios...
I bought a while ago an SLI Bridge from EVGA and it that doesn't work properly, it makes my cards have some strange artifacts and well I thought "I may try the new bios", tried it but I haven't got rid of artifacts... So I thought in testing each card which they worked flawlessly when not in SLI, So I replaced my "new" bridge and it seems I've got everything fixed ( Yeah spent some money on a bridge with about 2 weeks and it isn't working, quite bad evga

)
Resuming I've updated my bios
*, and well the best part is here, previously I couldn't get more than 15+ on GPU Offset with 550+ on Memory, keep in mind that my cards boost out of box to 1228/1215, now with this new bios I can OC alot more! It's working at 70+ GPU Offset and 550+ on Memory, which result in 1293/1280 Mhz which is an awesome OC In my opinion for two GTX 670 FTW's, thanks alot evga for this update!
* Keep in mind that I've modded by my own my bios ( the newest ) to take advantage of full Fan speed ( 25-100% ), that way I can keep cards under 63Cº at the OC'ed speeds!