halcyon, are you psychic or something?
Similar thoughts have been passing through my head in reference to an upcoming SPCR article...
I won't give away the rest of the article (it'll be up in a couple of days) but I will copy/paste my BTX-related comments that appear as an addendum at its end:
One aspect not touched upon in the description of the A64's on-die memory controller is its impact on motherboard design. Because the memory controller requires equal length traces to each of the RAM pins, and the traces need to be as short as possible to reduce latency, there is much less variety in motherboard layout than with designs for previous processors. These requirements make it unlikely that you will ever see a BTX form-factor A64 motherboard. BTX shoves the CPU up to the edge of the board, and turns the RAM at 90° to it, along the other side of the motherboard. Not an impossible arrangment, but nowhere close to ideal.
Some AMD engineers have been quoted as saying they will not be supporting BTX. If Intel does manage to bully BTX onto the Intel motherboard market, you may be forced to buy a completely new case and PSU if you want to switch from an Intel to an AMD product.
There is alot of resistence to BTX, from, well, everyone except Intel. The case manufacturers don't like, the mobo guys don't like, Ati and Nvidia absolutely hate it, and AMD and Via (the #2 and 3 chip makers) have said that they have no interest in it at all.
And why should they? Its design is almost soley the result of Intel's reliance upon the Megahertz Myth to sell chips. And the resulting thermal runaway in their CPU's.
And from an airflow/noise standpoint, it's not much better than ATX is. Sure, it moves the CPU closer to the incoming air (something that can be done with an ATX mobo and a ducted case anyway, just look at the ARM systems) but in doing so it sacrifices the airflow for every other component in the system.
From a quieting/cooling standpoint, its the VGA that needs the biggest leap in cooling, and BTX actually makes things worse there instead of better. GPU's are the single fastest growing source of heat in a PC: CPU's have really slowed in their rate of heat recently, whereas the new generation of GPU's is going have wattages 30% higher than their predessors.