What about extending the RAM through an SD Card?


GoldenSun3DS

Member
Joined
Apr 7, 2012
Messages
61
Age
29
Location
Mars
Basically, would it be possible to have a background process similar to Readyboost on PCs that uses space on the SD Card for extra RAM?
This could give the Pandora a pretty good speed up.

My laptop (normally) does Super Mario Sunshine emulation at a steady 5 fps in levels. After I reformatted my SD Card to exFat with 32MB blocks (yes, mega bytes, that's not a typo) and reserved all 7.21GB to readyboost, Super Mario Sunshine emulation shot up to 7-9fps and Mario Kart Double Dash emulation shot up to around 20-25 fps (MKDD emulation was around 15fps before).
Also Playstation 1 emulation that just barely ran at full speed with with minimum settings and sound errors (trying to fix the sound issues slowed it down) was able to be cranked up to max settings with HD and improved textures at full speed after reserving the space on the SD Card for Readyboost.

That's how much of a difference a program like Readyboost can make.
 
That only helps if you have a program that needs more RAM than the Pandora has.
 
There could be plenty of programs and games that could use the extra RAM.
I'd imagine that tough to emulate systems, like the DS, would need more RAM to run properly.
.
.
DS emulation on the Pandora could most definitely use the extra RAM. My laptop can't even emulate Golden Sun Dark Dawn (a DS game) at full speed without using Readyboost, and it has 2GB of DDR2 RAM. After adding 7.21GB of virtual RAM with readyboost, it's able to emulate Golden Sun Dark Dawn at full speed.
.
Imagine how much better DS emulation on the OP Pandora could be if you simply added virtual RAM through one of the SD Card slots.
 
I'd imagine that tough to emulate systems, like the DS, would need more RAM to run properly. . . DS emulation on the Pandora could most definitely use the extra RAM. ...
I suspect that you'd be wrong in the case of Pandora. If you're running Vista or Win 7 you really need 4GB of RAM to get decent OS performance, this is why you're seeing a good increase after using ready boost.
 
So we have something like that in the Pandora it's called a swapfile.. we even have a nice utility to enable them.. 

The thing with PCs is that Windows is a memory hog 2GBs of RAM is too little for it to run effectively and it starves applications that need any amount of memory, if you ran light weight Linux distribution on your desktop 2GBs would be enough for most game related things.

Even with the Pandora's 512MBs of system RAM it's enough for any gaming related use..

Edit: did you know your beloved 3DS only has 128MBs of system ram?
 
Last edited by a moderator:
Also, swap is slow.

It only makes sense if:

  1. Your system is going to freeze if it doesn't get more RAM
  2. You have a lot of idling processes not doing anything
 
Well it is only plastered on every Sig you have.. I was just giving an example of an efficient system running on low amounts of memory.. Memory isn't a hindering factor in DS emulation, it's most likely the CPU and GPU
 
What large games like Runescape? In order to bump up the graphics settings you'd need more RAM.

@TrashyMG: Efficient systems are good, but efficient systems with even more RAM are better. That's why I created this thread.
 
If you need a swap file it slows games won't run at full speed.

There is a reason why we have a RAM.

It's so much faster than any other Memory type we have can access with the Pandora.
 
Sure since this is a browser game and firefox is such a memory hog a swap may improve the situation, but not make it playable.. Runescape would be near impossible to play on the Pandora because it runs off a browser and flash and html5 methods have not been optimized on it.. However if you are talking about a game at the same scale of features as Runescape that was designed and optimized for the Pandora I think 512MBs would do just fine.
 
Last edited by a moderator:
What large games like Runescape? In order to bump up the graphics settings you'd need more RAM
So I just profiled Runescape with high graphics setting. When it was fully loaded and I was in the world doing stuff, the java plugin consumes 35MB of RAM and the web page 50MB. Altogether Runescape requires at most 85MB of RAM and in fact cab probably use less if someone were to streamline the html better. Runescape will not benefit at all from additional RAM, whether it is physical or virtual on an SD card.
edit: I should be sure to mention that this was on my desktop. I wasn't able to get Runescape running on the Pandora but I have no reason to believe that the standalone app would take any more memory than the browser based one.
 
Last edited by a moderator:
Also: We already have what you're thinking of. What windows nowadays call "Readyboost" is what in the linux world is called a "Swap file" more or less, with the additional idea that you may hotplug it. There are utilities in the repo called "Swap tool" and similar that does exactly that - Sets up a swap file on an SD card which works as an extension of the memory. But, as has been pointed out, this is only effective if the emulator or whatever is slow because of memory starvation (and even so, it is slower than "real" memory). This happens a lot when the OS itself is from Macroextrabigsoft, but with our tiny Ångström, not so much. 

So: Yes, it helps, in particular cases. If you have a classic CC Pandora with 256mb memory and try to run Firefox, then your pandora will struggle. A swap file will help extend your memory and make it run smoother. If you have a newer model, you won't need it since you already have 512mb of the real thing. However, Firefox is the big kahuna burger when it comes to memory hungry pandora applications. Not many emulators will get close to that memory footprint, not even with the biggest games loaded.
 
There is nothing on the Pandora that gets a speed up from swap. Swap can only give a speedup if your program benefits from OS caching (so it can benefit more from caching because idle processes get moved to swap, freeing real RAM for caching), or if it somehow makes a time/space tradeoff itself based on the amount of memory it can allocate.

The main use of swap is to be able to do stuff that would otherwise be impossible (e.g. use firefox with many tabs on a 256MB Pandora), not to make stuff run faster. Swap space is always a lot slower than RAM (otherwise why would anyone bother to have real RAM, just use a 64GB SD card as RAM ;) ). You can't make stuff go faster by using slower stuff.
 
Altogether Runescape requires at most 85MB of RAM and in fact cab probably use less if someone were to streamline the html better. Runescape will not benefit at all from additional RAM, whether it is physical or virtual on an SD card.
Don't forget the VRAM, its usage has to be added to those 85MB as we don't have any.
 
There could be plenty of programs and games that could use the extra RAM. I'd imagine that tough to emulate systems, like the DS, would need more RAM to run properly. . . DS emulation on the Pandora could most definitely use the extra RAM.
No. The only benefit is the ability to load larger zipped ROMs - for units with 512MB of RAM that's barely relevant since they should be able to load 256MB zipped ROMs fine. If I made an option to unzip it to a temporary file somewhere that benefit would go away. You can of course just unzip the ROMs yourself.

Even real RAM (not flash used like RAM) would be dead slow over the SD card interface, there's no point. Of course there isn't such a thing anyway so that's moot.

I don't know about the situation with your laptop, but the reason why Readyboost ever helps at all is not because it adds RAM to your system but because random access times on an SD card are typically better than on a harddrive (but the throughput is much worse). So if you're using something that does a bunch of seeks, like loading a ton of small files, that can help. None of this matters for a mobile device like Pandora whose storage is already NAND-based and not a harddrive. And I doubt it'd make a big difference with the emulators you mentioned, you probably had something weird going on.
 
Last edited by a moderator:
How fast is the Open Pandora's RAM? Isn't it something like 166MHz and 200MHz for the GHz model?

I managed to get my SD Card's write speed on my laptop up to a range between 4MB/s to 4.3MB/s (by formatting it to exFAT with 32MB blocks).

How fast is 1MHz in MB/s? Is it like 1MHz = 1MB/s, or what?
 
More likely 8 MHz = 1MB/s, but I don't really know...

I believe pandoras max out at 16MB/s (sequential write) eshared between the SD cards
 
Last edited by a moderator:
Back
Top