Wii U Memory Map


Recently we have published a lot of articles about the recent Xbox One and Playstation 4. This time we bring new information about Wii U, maybe the most “secret” system out there.

First we will see a visual representation of the memory map inside Wii U:

wii_u_mem

As we can see, the total amount that a game can use is 1 GB (code + data). This is not a surprise, Nintendo revealed this in one of the past Nintendo Directs. But additionally we can see the amount of memory reserved by the rest of elements.

We have 2 different memory zones: MEM1 and MEM2. All the application code and data are placed in MEM2. The system reserves all of the memory except for the area allocated for the application. The system reserved area (another Gigabyte) is not available to applications (although this can change in the future and maybe it will allocate 512 MB more for applications).

MEM1 is reserved for graphics libraries (although over the time the size of MEM1 will be decreased for graphics libraries). Therefore, applications cannot use MEM1 directly.

wii_u_mem2

At this stage, we have got cached and uncached memory. Cached and uncached accesses were available to Wii apps, however, uncached access is not available for Wii U.

  • T.E Starkey

    Can you explain. Will memory for games or the OS be decreased over time?

    • vgleakscom

      Yes, of course, with new sdk’s, tools, nintendo could free memory that could be available for applications (games) but right now the limit is 1 GB.

      • tipoo2

        Any idea how much is just reserved as a safety for future, vs actually used right now? Reducing RAM use would be nice, but that’s always a tradeoff between RAM reserved and system speed, which the Wii U is already not optimal at.

        • vgleakscom

          Well, Nintendo was unsure about the memory reserved for applications. They always said that it will be between 1 and 1.5 GB so we can think that the maximum amount that they could free in the future could be another 512 MB. Right now 1 GB is reserved for OS tasks. I’m not sure if this memory is totally used in the current OS version

  • tipoo2

    This seems very odd…The main memory bandwidth can only be a maximum of 12.8GB/s, reading the markings on the RAM banks. I thought the 32MB eDRAM would be the one saving grace on the bandwidth story, but if that isn’t programmable or used as a cache the situation seems even worse.

    And what about that smaller eDRAM bank and SRAM bank on the GPU? Are those just for backwards compatibility?

    • Elem187

      Thats nonsensical. Why would they put very very expensive eDRAM into the system if they weren’t going to use it as customizable cache….. Nintendo is about as cheap as any company can get, if they weren’t planning on using MEM1 to speed up their 12/gbps throughput, the eDRAM wouldn’t be there in the first place. Sounds like this analysis is a bit off. Did they get this information from an old dev kit?

      Without using the massive bandwidth of the eDRAM, Nintendo could have shaved almost $50 off the retail price. It was put there for a purpose, and just saying Nintendo are idiots is massively underestimating them. They take their customized hardware pretty seriously.

      • tipoo2

        A recent interview with the Nano Assault dev claimed this was wrong, they can in fact use the eDRAM. I guess this is either plain wrong or just an early dev kit.

        Although, hypothetically if the eDRAM was automatically managed for best performance that could be a reason why it’s not directly writeable to devs.

  • Paladinrja

    Where the fuck did this come from? Haha double-wide, short 5 stage pipes on such fast interconnect, SIMD and NEON. Forget the 1GB you’ll be lucky if the system even tips it with its nose. Unless you fuckup like EA and launch titles with missing PU’s, thats classic btw concurrancy being kinda important and all with MCM.. Anyway, 3 PPC cores and 1 Cortex core. Nice, hope it works out for Ninty this package is inspired.