How would you describe target specs given no-one has seen the new memory, use the fastest available memory at the time? Custom or semi-custom memory with a GDDR5 interface does not make sense!
As to drawbacks, it's faster, requires less power and produces less heat. Manufacturing memory with TSVs and stacking like on like has been done for 4 years so it's not new.
As to the SOC and MCM that both games consoles will be using, that's not a debatable point but is also being overlooked in BY3D for the most part. It's process optimized building blocks with differing die size and processes that are TSV connected to a SOC substrate with overflow being assembled by TSMC using TSVs and 2.5D transposer (MCM).
IBM and AMD have been working together on this since 2008. Micron has been working on the memory solutions to feed HSA HPC SOCs.
2013 is the target date a number of industries have been working toward and Game console volumes are kick starting the technology and making it economical.
I'm getting tired of repeating myself and I'm sure some of you are getting tired of reading my posts. I've provided the cites and created a thread which has a
summary of what makes a next generation game console possible, I suggest you read through the cites on the first page.
Your comment about 3D transistors for instance, which won't happen till 14nm, is an example of your misunderstanding of the technology. I've made similar gaffs on Neogaf <grin>.
Edit: For example, I insisted Gstreamer was in the PS3 since Firmware 3.0 incorrectly and Massa (below) corrected me (LGPL) and forced me to rethink my position. Turns out My first guess on BY3D which was Adobe open source AVM+ was correct which I dismissed later as SNAP and GTKwebkit indicated Gstreamer was the future which may still be true but I couldn't believe Sony would invest in AVM+ and then rewrite/replace most of the XMB routines later this year. Should have known as Netflix had to port a complete QTWebkit plus gstreamer to the PS3. I also insisted the XMB would be rewritten to support CairoSVG when it's already OpenVG SVG as I didn't know about EGL which provides support for OpenVG + OpenGLES2 and Cairo can be edited to use OpenVG for the 2D parts of Cairo and use OpenGLES2 for the 3D parts of CairoGL= Cairo-eGL
I'm really surprised that given AMD has admitted that their process optimized building blocks include "(CPU, Cache, DRAM, GPU, analog, SSD)" and the popularity of SSD for very fast loading and solid state hard disks as well as DRAM inside a SOC that no-one is speculating on this. The rumors of 16 gig Flash = SSD sorta supports this.