AMD Zambezi news, info, fans !

[-Boris-]

Doubling the FPU's takes massively more die area, meaning more power usage, and you can't clock it as high if you want to remain within a certain TDP.
Floating point units are much more complex than integer units, and take up much more die area.
instruction sets like SSE, AVX use the FPU primarily.

You just repeated the things I questioned without any arguments. Each FPU takes 1% of total die are, for a total of 4% of an full 8c BD. Of course it needs other stuff as well in the front end, but even if you say that all that takes as much space as the FPUs themselves (which is absurd) there is still just 8% larger die. And Turbo is made for just these kind of things, so frequencies shouldn't be a problem. Besides, do you honestly think it would make such a large impact on frequencies? You can chop of half the power usage with lower current and a few hundred MHz lower clocks. Even if power usage rose by 25% (again absurd) it wouldn't mean to much in lost base frequencies, and probably close to nothing in max frequencies.

You do realize that in order to get 8 *full* fpus the old way, you have to replicate front ends ,integer exec. units and L1 and L2 caches ,right? This leaves you with wasted and doubled die area that will mostly sit idle (especially fp unit). Beaty of bulldozer is exactly in maximizing perf./watt/mm^2. Btw ,the most power hungry part of the core is usually fpu...

No, you wouldn't need to duplicate most of the processor. SB has an full AVX unit per core, didn't need to duplicate most of the core to get that working. The same when Phenom got an 128bit FPU. Of course you need som extra circuits to make it work, but not more space than the entire FPU. And as I just said, the FPUs themselves eats up just 4% of a full module.