3.4GHz will be the stock clock of the new X4 965, making it the fastest quad-core on the market, along with the Xeon X5492 from Intel, which is a 150W part, though. The 965 will keep the 125W TDP, as is mentioned on ASRock's website. It will feature the same cache as the 955 and it will be a Black Edition.
We saw here that the Phenom II X4 955 often beat the Core i7 920 in gaming due to its higher frequency. With an extra 200MHz, the 965 will probably be able to compete with the Core i7 940's performance in many cases, which currently sells for $587.17 on NCIXUS.com. However, AMD will most probably launch it at a very competing price, which will force Intel to cut prices on its Core 2 and maybe Core i7 line.
This time, I would not be surprised if the Phenom II X4 965 had a bit more overclocking potential than the 940 and 955. It would be somewhat disappointing if on air it also maxed out at around 3.8GHz, which would be only a 400MHz increase. This is what we will see if Neoseeker gets his hands on one!