4.2GHz FX-4350 is the fastest
AMD plans a lot of Vishera processors, including some quad-cores, and the new series is scheduled to launch in Q4 2012. The fastest quad-core from among them is called AMD FX-4350. It works at 4.2GHz native clock and 4.3 GHz turbo, has 12MB cache and 125W TDP.
This processor is set to replace currently available AMD FX-4170 clocked at the same clocks, but based on the older Zambezi core. The runner up is FX-4320 a 4GHz native clocked quad core with 4.2GHz turbo and 8 MB cache, all at 95W TDP.
This one should replace the AMD FX4150 quad-core with 12MB cache and 95W TDP and 3.9GHz / 4.1GHz with Turbo, naturally based on older Zambezi core. The last of three quad-cores is AMD FX-4300 clocked at 3.8GHz, but capable of hitting the magic 4.0GHz figure a dash of Turbo. It has 8MB of cache and 95W TDP.
All three quad core Vishera 32nm cores support AM3+ motherboards, DDR3 1866 and were originally expected in mid Q3 2012, but they now have the late October launch tag at their sleeve.
The new Pilediver core should result in higher core performance at the same clock compared to Zambezi core and should have increased power efficiency, resulting in lower heat output.