Reported memory on Xperia M5 - ONLY 2.53Gb - NOT 3Gb??

[icstm]

Hi all,

What is the memory (RAM) reported on your system?

The spec says 3Gb, but the phone reports substantially less than than (either 3072Mb or 3000Mb).

In my case  it is only 2.53Gb.

I am not talking about free or availible ram, I am talking about the total.

[icstm]

[_alexdon_]

You will get around 2.6 GB available out of 3. That is because RAM memory is sold in multiples of 10, so you basically get 3000 MB. But if you convert to binary, available is 2,79. From that, you get to use a bit less.

[icstm]

Thanks but if you read my top post, you will see I factored that in.

And BTW, ram unlike HDD is normally not sold that way, but just in case I factored before posting.

The Z3 is close to the number you suggest of 2.7something

[MarlonUk1]

@icstm, also aide from @alexdon's answer, companies tend to market this specs rounded up, i.e. a camera that is 5megapixels is only actually 4.3mp , as the whole sensor is not really used, so is with ram and internal memory and sd cards.

to know more about your phone's tech specs, you can read it here http://developer.sonymobile.com/downloads/whitepapers/xperia-m5-e5603-e5606-and-e5653-white-paper/

[_alexdon_]

I think any memory is sold that way, because it will be converted to binary. At least that's what I learned from others.

[icstm · Accepted solution]

Got the answer elsewhere - as I said above I had taken into account both the marketed value or the whitepaper value (which is exactly 3Gb); I had then allowed for binary shinanigans. Therefore your rationale did not add up.

It appears that the M5 uses a compressed ram disk, known as zram. This is a space where the phone can store more cached apps, but with a slight delay, but still better than loosing them from ram altogether.

You will find a folder on your phone to validate this:

/sys/block/zram0/compr_data_size

Personally I find this quite interesting. About 20 years ago I would do something similar on Archimedes computers, to speed up working on files.

[YoGem]

Actually the issue is different, the Zram is just swap, not part of the ram equation.

We are all forgetting about a small amount of ram dedicated to the graphic card. In few words, the missing ram is used by the graphic card.

[icstm]

Zram is compressed ram, rather than a swap file to the static ram storage.

But you are broadly right.

It is 3GB total, about 500Mb for graphic and device cache etc.

So that is your 2.5Gb

Then about 500 zRam.

So you can never have less than 500Mb used in the active RAM.

Then the rest of active.

Finally your machine can use and replace the cached memory (which itself if often compressed into the zram.

Rather odd to have ZRAM these days, but hey ho