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blu
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(11-19-2012, 01:42 PM)
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Ok, I think it's about time we tried to put all known Wii U specification things into its own thread and try to have a civil discussion.

Hard facts (either publicly disclosed, or a non-public leak which can be vouched by somebody trustworthy on this very forum):
  • MCM design: GPU+eDRAM die and CPU die on the same substrate.
  • 2 GB of DDR3 memory @800MHz (DDR3-1600), organized in 4x 4Gb (256Mx16) modules, sitting on a 64bit bus (@800MHz). That gives a net BW of 12800MB/s (12.5GB/s). We can conveniently refer to this pool as 'MEM2'. Currently 1GB of that pool is reserved for the OS.
  • 32 MB of unknown organisation, unknown specs eDRAM, sitting with the GPU. We can conveniently refer to this pool as 'MEM1'
  • Tri-core CPU @1.243125GHz, codename 'Espresso', binary compatible with Gekko/Broadway, featuring 3MB of cache in asymmetric config: 2x 512KB, 1x 2048KB; CPU cache is implemented via eDRAM. Sans SMT. SIMD is same 'paired-singles' 2-way SIMD found in Gekko/Broadway. Fourth Storm's thread discussing the high-res CPU die shot produced by Chipworks on GAF's request.
  • AMD R700-originating GPU @550MHz (R700 is AMD architecture codename 'Wekiva'), evolved into its own architecture (AMD architecture codename 'Mario'), relying on MEM1 for framebuffer purposes, but also for local render targets and scratch-pad purposes. Thraktor's thread discussing the high-res GPU die shot produced by Chipworks on GAF's request.
  • Memory access specifics: both MEM1 and MEM2 are read/write accessible by the CPU, both subject to caching. GPU in its turn also has access to both pools, and is likely serving as the north bridge in the system (an educated guess, subject to calling out).
  • System is equipped with extra co-processors in the shape of an ARM (unknown architecture) and a DSP core (again of unknown architecture) primarily for sounds workloads.
  • BluRay-based optical drive, 22.5MB/s, 25GB media.

Immediate logical implications from the above (i.e. implications not requiring large leaps of logic):
  • Not all WiiU CPU cores are equal - one of them is meant to do things the other two are not. Whether that is related to BC, OS tasks, both, or neither, is unclear.
  • When it comes to non-local GPU assets (read: mainly textures), WiiU's main RAM BW increase over nintendo's most advanced SD platform (i.e. 5.47GB/s -> 12.5GB/s) hints that WiiU is mainly targeted at a 2x-3x resolution increase over the Wii, or IOW, 480p -> 720p.
  • The shared access to MEM1 pool by the GPU and CPU alike indicated the two units are meant to interact at low latency, not normally seen in previous console generations. Definitely a subject for interesting debates this one is.

credits:
  • teardown revealing DDR3 modules courtesy of PC Perspective, Anand and iFixit.
  • U-CPU clocks and architecture details courtesy of marcan.
Last edited by blu; 02-18-2013 at 12:04 PM.