Prototypes of AMD's quad-core K10 Agena desktop processors are already running fine. FUD Zilla had a chance to witness one, they saw a 1.9GHz version of this 65nm processor:
It works at 1.9 GHz or 1908 MHZ to be precise with multiplier at 9.5 and the bus speed of 200.9 MHz. The 0.5 multiplier settings are back. You can also clearly see that we are talking about quad core processor with four cores and four threads.
Agena at 1.9 GHz has 4x64KB L1 Data cache memory, 4x64KB L1 for Code, 4x 512 KB L2 cache and finally all cores share the 2048KB L3 cache.
They also tested how well it overclocks. In this article they show a CPU-Z screenshot on which you can see that they overclocked the part to 3042.4MHz by increasing the FSB to 320MHz. This went pretty smooth, but they did have to increase the voltage from 1.273V to 1.297V.