Bulldozer will be utilizing a Quad-channel memory interface.
G34 Enterprise, not BD Zambezi, uses quad-channel DDR3 memory. A consumer board with 8 DIMM slots is almost laughable on its face. However, Zambezi will natively support DDR3-1866 (which, btw, the woods are full of AM3 boards so qualified).
A Zambezi
module will consist of
2 integer cores. Each
integer core will have
quad instruction pipelines ...
A quad core Zambezi will consist of
two modules. An eight-core Zambezi will consist of
four modules. Each grouping will share the L3 Cache and 'north bridge'.
Additionally, since AM2+, the arch has supported
split power planes in all reference designs.
With that being said buying an AM3 motherboard may or may not be compatible with Bulldozer... but the question is... would you want to use a motherboard that only supplies half the potential performance of Bulldozer in terms of memory access requests?
There is so much wrong with this it is hard to know where to begin. First, it is based upon your 'strawman' argument of quad-channel memory. What does "half the potential" and "memory access requests" mean? For each 10% increase in the NB/IMC speed, memory bandwidth increases 3-4% and reduces latency 3-4% in the current arch. There is no reason to expect Zambezi will be any different. Since 'enthusiasts' are now clocking the NB/IMC over 50% why would AMD
bother with a 5% increase in bandwidth and latency with triple channel memory, much less another 5% with quad channel, when they may simply boost the speed of the NB/IMC (or 'uncore' as the Intel fanboys call it)?
I think that today's AM3 motherboards, even if compatible, defeat the purpose of purchasing a Bulldozer.
We all know what opinions are like. Your opinion happens to be wrong.
I also have yet to see anyone resit the temptation of buying a new motherboard with a new CPU of a different architecture.
Most folks who had compatible i945 board (for Core 2 Duo's) saw themselves upgrading to a new i965/i975 motherboard.
We all know what opinions are like (Is there an echo in here?). When you purchase a new motherboard you must also purchase a new OEM copy of your OS, unless, of course, you violate the terms of your EULA and 'pirate' the software.
There is no reason to even discuss this given the support and backward compatibility AMD has offered over the last few years. Feel ripped off yet when someone updates their BIOS, 'pops' a hex-core 1055T in a three year-old motherboard and reuses their DDR2? (And NO, I am not implying Zambezi will include a DDR2 controller)
Also.. even if Bulldozer is pin compatible.. it doesn't mean that it will work in today's AM3 boards. Voltage regulation as well as BIOS firmware updates play a role. It will also depend on the memory controller aboard Bulldozer.
You might have missed this: Since AM2+, the mobo arch has supported
split power planes in all reference designs which allow the dynamic manipulation of core voltages and PLL, dedicated temperature sensor circuits for each core, gating, and the memory controller, including separate sleep states, voltages and frequencies for the northbridge. HT links, too.
Too many questions therefore no answers can be given with certainty.
AMD (unlike Intel with s775) has never released same-socket incompatibilities (though s754-s939 was not their finest hour), and though there are no guarantee that OEMs will update motherboard BIOSs - if the past is any predictor - AMD partners have been great with updates on 'enthusiast' boards, so ... what it looks like you are saying is, ""Since I own an Intel processor looks like I'll have to buy
another new motherboard when the next gen Sandy Bridge 'E' comes out while AM3 motherboard owners will be smiling all the way to the bank""
That does not mean that AMD and their partners will not tempt new builders with 'enhanced' AM3+, but other than PCIe Gen3 and maybe a few goodies from the enterprise side (like HyperTransport 3.1 and the 'HT Assist' probe filter,
not quad channel RAMs), there are unlikely to be any significant performance-based enhancements (other than the BD modules themselves). An update to the south bridge?
for USB3 headers? - LOL