Keep in mind its likely that AMD will have EIGHT core Bulldozers for around or maybe even less than a 2600k, thats fully overclockable, on a vastly cheaper(and working
) mobo, that will have a 3.5-3.8Ghz stock clock speed, that can do turbo on ALL cores at 500Mhz, meaning most load will have the whole chip at 4-4.3Ghz without overclocking, and it can go significantly further still with less than all the cores loaded, potentially 4.5-4.8Ghz with 1-2 cores loaded, at stock.
Overclocking should be godly, gate first IS better than gate last, but gives lower yields, bad for AMD, the chips that work will be better though. Its got a slightly longer pipeline so the design lends itself to MUCH higher clockspeeds than Phenom's do.
But the main point here is, no one knows what Bulldozer bits will be seen at Cebit, so its not worth talking up into crazyness yet.
Firstly its VERY common for companies to show only reporters, or bigwigs in the industry new parts behind closed doors. Cebit has a public and a private side to it, some products are on show for everyone, some are behind closed doors NDA covered briefings only.
All we know is Bulldozer should be at Cebit, we have no clue if a single Bulldozer piece of information will end up shown to the general public. We have no idea if there will be benchmarks and we have no idea if anyone will get to use a system with one in.
As for the 50% stuff, its SO vague and we don't know really know what its in with a lot of fake slides about.
AFAIK the 50% thing was said AGES ago and was first mentioned in regard to the server space, where switching out a 8 core server chip would beat a server chip by 50% quite comftably as a drop in replacement. Server loads vs home use loads can be incredibly different.