With the risk of being misunderstood, I will have a try at explaining Bulldozer and AM3+.
Bulldozer is indeed a true eight core processor since it has eight integer units, however, unlike Intel using Hyper-Threading to pump out maximum performance from each core, AMD tried to increase efficiency, lower costs and decrease die size of it's not-at-all bad architecture trough sharing various logic components like Fetch and Decode, Floating Point Unit and Level 2 cache, components that aren't always fully utilised and consume more power in their initial dedicated forms.
All this saved power may then be used to pump up those cores to raise processing performance trough speed.
Unlike old single core processors ( like my Sempron 3000+

) which have true efficiency thanks to their single integer/single FPU, single L2 cache design, multi core processors like Bulldozer and Nehalem suffer from programing inefficiency. One way to increase performance is to raise core clock but we all know that higher clocks translate into higher power consumption and temps. High temperatures can be lowered with better coolers but power consumption is limited by motherboard TDP design, since not all manufacturers allow high TDP parts on their mobos for economic reasons.
From my point of view, AMD's approach to efficiency trough architectural improvements is logical and superior to Intel's, even though it's a bit too late.
AMD and, later, Intel developed features like Cool'n'Quiet and EIST which decrease clock and voltage of unused cores, but this didn't solve TDP issues so they introduced Turbo to raise performance of used cores while staying within TDP limits.
These features depend in some measure of chipset design. AMD wants and needs Bulldozer at it's peak efficiency and performance and to obtain it they will introduce AM3+/AM3b and 900-series chipsets.
If you already own a 7/800-series motherboard and your manufacturer offers you compatibility with the new FX chips then keep it. But if you are buying a new PC/fully upgrading your PC/have too much money and don't know how to spend it then a 900-series mobo will be the logical buy.
Pffffff too much writing

.
Next summer I'll be upgrading too to an FX-8130P/980GX/DDR3 because my 1,8 sempron is hopelessly slow these days. Sandy Bridge just doesn't float my boat

).