Frybo
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Rpi max ram

Fri Apr 21, 2017 6:59 pm

I'm guessing arm 32bit has max ram of 4gb but what about arm 64 bit

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DougieLawson
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Re: Rpi max ram

Fri Apr 21, 2017 7:09 pm

Frybo wrote:I'm guessing arm 32bit has max ram of 4gb but what about arm 64 bit
The first Raspberries had 256MB, the next ones had 512MB (and that includes the Zeros), the latest ones have 1GB. That's it, the hardware can't address more than 1GB so you can't add more, the RPF folks can't build current BCM2837 Raspberries with more than 1GB. End of story for this generation. To go larger than 1GB needs a new SoC.
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fruitoftheloom
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Re: Rpi max ram

Fri Apr 21, 2017 7:18 pm

Frybo wrote:I'm guessing arm 32bit has max ram of 4gb but what about arm 64 bit
https://en.wikipedia.org/wiki/RAM_limit

Though as DL stated you will not get more than 1GB in a current Raspberry Pi / CM...
Thinking outside the box is better than burying your head in the sand...

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 8:25 pm

U can add ram using swap what the max ram for that

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 8:27 pm

Froot of the loom thats for intel / amd not risc / arm prosesors

Heater
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Re: Rpi max ram

Fri Apr 21, 2017 8:31 pm

4GB.

You can add swap space but you cannot exceed the addressing capability of a 32 bit CPU. That is 32 bits.

Swap is great till you have to use it. Then everything gets thousands of times slower.
Memory in C++ is a leaky abstraction .

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Re: Rpi max ram

Fri Apr 21, 2017 8:32 pm

Frybo wrote:Froot of the loom thats for intel / amd not risc / arm prosesors
...from the link:

Modern 64-bit processors such as designs from ARM, Intel or AMD are typically configured with 48 address pins (supporting 256TB of memory)
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Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 8:34 pm

Thx mr heater but isnt the rpi 3 64 bit can i add more than 4 gb the anser is yess but wat is the limit

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kusti8
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Re: Rpi max ram

Fri Apr 21, 2017 8:35 pm

Frybo wrote:Thx mr heater but isnt the rpi 3 64 bit can i add more than 4 gb the anser is yess but wat is the limit
The OS runs in 32 bit mode so you're still limited. But swap is so slow that it is not really usable, only to protect yourself from unexpected crashes if there is a shortage.
There are 10 types of people: those who understand binary and those who don't.

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 8:36 pm

So my theatrical max ram on pi 3 is a cople tb

Heater
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Re: Rpi max ram

Fri Apr 21, 2017 8:37 pm

Hmmm...

Conceivably on could install a 64 bit Linux onto a Pi 3 and setup a terabytes of swap space.

Would be slow as hell if you had to use swap though. Not a workable solution.

1GB is it for now. I'm afraid.

But, hey, that is loads more than one actually needs for the Pi's original intended purpose.
Last edited by Heater on Fri Apr 21, 2017 8:39 pm, edited 1 time in total.
Memory in C++ is a leaky abstraction .

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kusti8
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Re: Rpi max ram

Fri Apr 21, 2017 8:38 pm

Frybo wrote:So my theatrical max ram on pi 3 is a cople tb
Yes, except it won't work on a 32 bit OS like Raspbian and there is absolutely no need for it...
There are 10 types of people: those who understand binary and those who don't.

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Re: Rpi max ram

Fri Apr 21, 2017 8:39 pm

Frybo wrote:Thx mr heater but isnt the rpi 3 64 bit can i add more than 4 gb the anser is yess but wat is the limit
NO, the design of the BCM283x SoC is the limitation.
Thinking outside the box is better than burying your head in the sand...

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 8:44 pm

wat about soc is the botle neck

fruitoftheloom
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Re: Rpi max ram

Fri Apr 21, 2017 8:47 pm

Frybo wrote:wat about soc is the botle neck
https://www.raspberrypi.org/documentati ... herals.pdf
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rpdom
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Re: Rpi max ram

Fri Apr 21, 2017 8:51 pm

Frybo wrote:wat about soc is the botle neck
simples. It has a max RAM space of 1GB. Wat(sic) the ARM can address isn't the limit.

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Re: Rpi max ram

Fri Apr 21, 2017 8:54 pm

ok i get that the max phisacal ram is 1gb but what about the swap max it will be 3 gb corect

i tryed reading this


As is standard practice, the standard BCM2835 Linux kernel provides a contiguous mapping
over the whole of available RAM at the top of memory.



this is were i got the 3 gb
The kernel is configured for a 1GB/3GB split between kernel and user-space memory.


The split between ARM and GPU memory is selected by installing one of the supplied
start*.elf files as start.elf in the FAT32 boot partition of the SD card. The minimum amount
of memory which can be given to the GPU is 32MB, but that will restrict the multimedia
performance; for example, 32MB does not provide enough buffering for the GPU to do
1080p30 video decoding.
Virtual addresses in kernel mode will range between 0xC0000000 and 0xEFFFFFFF.
Virtual addresses in user mode (i.e. seen by processes running in ARM Linux) will range
between 0x00000000 and 0xBFFFFFFF.
Peripherals (at physical address 0x20000000 on) are mapped into the kernel virtual address
space starting at address 0xF2000000. Thus a peripheral advertised here at bus address
0x7Ennnnnn is available in the ARM kenel at virtual address 0xF2nnnnnn.
1.2.3 ARM physical addresses
Physical addresses start at 0x00000000 for RAM.
• The ARM section of the RAM starts at 0x00000000.
• The VideoCore section of the RAM is mapped in only if the system is configured to
support a memory mapped display (this is the common case).
The VideoCore MMU maps the ARM physical address space to the bus address space seen
by VideoCore (and VideoCore peripherals). The bus addresses for RAM are set up to map
onto the uncached1
bus address range on the VideoCore starting at 0xC0000000.
Physical addresses range from 0x20000000 to 0x20FFFFFF for peripherals. The bus
addresses for peripherals are set up to map onto the peripheral bus address range starting at
0x7E000000. Thus a peripheral advertised here at bus address 0x7Ennnnnn is available at
physical address 0x20nnnnnn.

Heater
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Re: Rpi max ram

Fri Apr 21, 2017 9:00 pm

Yes you can add swap files to get the 3GB address space that a 32 bit Linux kernel allows for user applications. Or a lot more if you use a 64 bit kernel.

Thing is, it's pretty pointless. If whatever you are doing requires such huge address spaces it will be incredibly slow when using swap. Not really something you will ever want to use.
Memory in C++ is a leaky abstraction .

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 9:02 pm

thx if u want to nog wat i want to do is run minecraft on pi 0

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 9:05 pm

and thx google bot for watching if u look at on line users u can see google bot

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 9:06 pm

Frybo wrote:and thx google bot for watching if u look at on line users u can see google bot
o and msn bot

Heater
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Re: Rpi max ram

Fri Apr 21, 2017 9:14 pm

Frybo,
thx if u want to nog wat i want to do is run minecraft on pi 0
Sorry, what?
Memory in C++ is a leaky abstraction .

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 9:15 pm

if u want to know wat i want to do its run mincraft on a pi 0

Frybo
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Re: Rpi max ram

Fri Apr 21, 2017 9:28 pm

btw i have 2 rpi 0 and 2 rpi 3 i made one a nas/vpn and i making a pi 0 portibal

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Re: Rpi max ram

Fri Apr 21, 2017 11:04 pm

deleted crud, please stay on topic!

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