The N64 will soon turn 30, yet hackers and homebrew developers are still finding out new things about the hardware – and one esteemed member of that community, Kaze Emanuar, just dropped a bombshell: the N64 has access to more RAM than we previously thought.
It's long been believed that Nintendo's 64-bit console has access to 4MB of RAM, with an additional 4MB being delivered via the Expansion Pak. However, as Kaze Emanuar explains in the excellent video below, there's actually an extra 0.5MB of available RAM from both sources – giving the machine a theoretical total of 9MB.
Where does this extra memory come from? Well, it can all be traced back to Silicon Graphics, the company which designed the N64 hardware.
The console has 4.5MB of RAM connected using a 9-bit data bus – with the 9th bit reserved for the GPU. Anything other than the GPU only has access to 4MB of RAM – unless you can find some hardware quirks, which Emanuar explains in the video.
Only one game actually uses this 9th bit effectively, and that's Zelda: Majora's Mask for its "Lens of Truth" effect. One of the reasons why it wasn't used all that much is the sheer effort required to extract what is, on paper, a rather small amount of extra memory (we won't attempt to pretend we understand all of this completely, however, so be sure to watch the video's incredibly detailed and informative middle-section for the complete picture).
Could this extra memory have been used in, say, Donkey Kong 64 to avoid the use of the Expansion Pak? Kaze Emanuar's research suggests that it wouldn't have made a dent in the amount of memory required to run Rare's 3D title, which is already using over 7MB of the console's available RAM.
The other issue, moving forward, is that modern-day developers who make use of this extra memory are limiting their potential audience, as it currently only works on actual N64 hardware – even the most accurate N64 emulator cannot replicate this feature.
It remains to be seen if the FPGA-based Analogue 64 will allow for this workaround, but in the meantime, this little hack is exclusive to real N64 consoles.