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Is 128MB Ram the most we'll ever need?

Posted: Thu Jul 09, 2020 12:59 pm
by chanunnaki
I'm getting a second MiSTer for my TV after I put my existing one inside my JAMMA cab, I was wondering if we'll ever need more than the 128MB ram add-on, perhaps a 256MB one, or has it been confirmed that 128MB is the most this project will ever need?

I'm not gonna wait either way and just get the 128MB now, just a curiosity that I thought I'd just ask.

Re: Is 128MB Ram the most we'll ever need?

Posted: Thu Jul 09, 2020 2:42 pm
by retrorepair
I'm interested in this too.

I would assume if N64 were to drop in the distant future it would probably need more than 128mb for some games (my memory may be failing me there).

Maybe DS? Were there any +128mb DS carts?

Re: Is 128MB Ram the most we'll ever need?

Posted: Thu Jul 09, 2020 3:18 pm
by dshadoff
128MB seems to be the most that is planned to go on an individual card, and it’s a lot of memory for machines from this era.
Expansion beyond this seems to be related to memory bandwidth - accessing multiple memory banks simultaneously by multiple components of the system; this implies that the next step will be to have a second memory card. The recent digital IO board frees up a GPIO bank for this potential use.
Of course, no such core has yet been written so this may not happen... but many of the next generation machines would have either multiple needs (CPU & GPU), or higher bandwidth requirements overall, so this is the next likely step..

Re: Is 128MB Ram the most we'll ever need?

Posted: Fri Jul 10, 2020 6:01 pm
by antibolo
retrorepair wrote: Thu Jul 09, 2020 2:42 pm I'm interested in this too.

I would assume if N64 were to drop in the distant future it would probably need more than 128mb for some games (my memory may be failing me there).

Maybe DS? Were there any +128mb DS carts?
I could be wrong but I think DS cartridges were not ROMs mapped directly to the CPU, so it shouldn't be necessary to run them from SDRAM. It's more akin to CD-based systems where the data is accessed sequentially and stored into RAM. At worst they would run fine from DDR memory.

Re: Is 128MB Ram the most we'll ever need?

Posted: Fri Jul 10, 2020 7:39 pm
by retrorepair
Interesting, wasn't aware of that.

Re: Is 128MB Ram the most we'll ever need?

Posted: Sat Jul 11, 2020 12:09 am
by ExCyber
retrorepair wrote: Thu Jul 09, 2020 2:42 pmI would assume if N64 were to drop in the distant future it would probably need more than 128mb for some games (my memory may be failing me there).
You might be misremembering megabit sizes as megabytes. Nearly all N64 games are 32 MB or smaller. I believe the exceptions are:

Paper Mario (40 MB? Seems like there's some debate on the real size)
Conker's Bad Fur Day (64 MB)
Pokemon Stadium 2 (64 MB)
Resident Evil 2 (64 MB)

Also, I wouldn't be surprised if it's feasible to put N64 ROMs in DDR3. The N64 cartridge interface is somewhat similar to the GBA interface in concept, but latching a new start address is surprisingly slow (> 1 microsecond). My understanding is that N64 games rarely run code directly from the cartridge after the earliest boot code because system RAM is so much faster than the cartridge interface, so small timing variations are probably more tolerable than on old-school systems.