Memory Poll on Pyra

How much RAM do you want?

  • 1GB (or less)

    Votes: 0 0.0%
  • 2GB

    Votes: 59 50.4%
  • 4GB

    Votes: 48 41.0%
  • 8GB

    Votes: 7 6.0%
  • 12GB (or more)

    Votes: 3 2.6%

  • Total voters
    117

_wb_

Microbe
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^^^ That's definitely a valid argument, _wb_. Not sure if it will offset microSD's speed problem. I guess having less parts laying around eroding and wasting way is a good thing. It could also make replacing dead nand easier, even though Pandora rarely have the problem. I guess ED can then sell replacement OS microSDs in his shop to help any unfortunate souls revive their bricked pyras. (But if so, the assembling of Pyra must be easier than Pandora. Pandora is a nightmare to take apart and put back together without breaking anything.)
People should be able to install a base install of the OS on a microSD card themselves, it's not hard to do, all we would need is a small tutorial on how to do it on various OSes (it would be trivial to make a PND so you can use a Pandora to put a Pyra OS image on a microSD card).

Also you shouldn't have to take apart your Pyra to replace the microSD card -- it would be in the same place as the SIM card, probably somewhere behind the battery. Relatively easy to reach, you probably don't even need a screwdriver.
 

Askarus

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Connecting the big SD-cards to SATA with UHS-II might be nice.

How's the  power consumption of SATA compared to SDIO?

Don't want to waste Power.
 

_wb_

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Connecting the big SD-cards to SATA with UHS-II might be nice.

How's the  power consumption of SATA compared to SDIO?

Don't want to waste Power.
I don't think storage without moving parts will make a real dent in the power budget, whether it is SD, eMMC or SATA. The idle power for all options should be quite close to zero, and the power when active (during transfer) will probably mostly depend on speed and the quality of the card itself -- faster will consume more power, but of course for a shorter amount of time. As long as we're not using spinning disks we'll be fine :)
 

SNESFAN

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Thank you for everyone so far who filled out the poll, I find the results interesting.

It looks like the majority feels 16GB is a solid target for the pyra internal storage. I don't know if that's influenced by ED posting prices on emmc modules or not, but it is what it is.

As far as what people find the most important, it seems that speed is trumping everything else, next preference being durability, then capacity, then upgrade ability, then capacity pretty much all in total and in order of preference. Cost is of little importance and so is power efficiency which was of little surprise.

What you can gather from this is that if all speeds are the same, and if both technologies have adequate durability, the capacity requirement is met, then it comes down to upgrade ability by general preference. Speed does have a majority preference so if the difference in speed is significant then the obvious decision is to go with the faster technology. So far that appears to be emmc as the fastest and kingston(is what ED is looking at) being a reputable flash memory manufacturer, if the speed ends up being negligible in comparison, then a 16gb microsd might be the best option. 

People reading this might have already come to that conclusion as well, but this poll verifies that with not so much inconclusive data. Also mind you, I'm still in the microsd camp.

Kind of split on if people want 2GB or 4GB of ram. 4GB would satisfy the 2GB people as well so that might be something to consider. I think it should at least be looked at as an option if it's not price prohibitive. But what I think is most important that speed and power efficiency is by double that of capacity,LPDDR is probably the best option there, if that's LPDDR2 or LPDDR3 is a case of what's available and compatible.

The preference for where to put an emphasis on funds for hardware development is close between to put money into getting more/faster ram and adding things like a combo emmc/microsd instead of just a emmc or whatever. So if the price of 4GB ram and a combo solution for internal is known and see which is more and if it's worth it to people to choose between the two.

would you all agree that's what this poll shows so far?
 
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slaeshjag

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If you missed what Exophase said: 4 GB of RAM would need *8* RAM-chips. That's a lot of chips.

It isn't really an option to go beyond 2 GB.
 

Askarus

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Connecting the big SD-cards to SATA with UHS-II might be nice.

How's the  power consumption of SATA compared to SDIO?

Don't want to waste Power.
I don't think storage without moving parts will make a real dent in the power budget, whether it is SD, eMMC or SATA. The idle power for all options should be quite close to zero, and the power when active (during transfer) will probably mostly depend on speed and the quality of the card itself -- faster will consume more power, but of course for a shorter amount of time. As long as we're not using spinning disks we'll be fine :)
If that's the case then I think I have my preferred setting:

(If everything fits onto the board and everything else works).

1: emmc 16GB via sdio

2: Micro SD and Sim card slot combined via sdio

3: Left SD-Slot with SATA and UHS-II pins

4: Right SD-Slot via sdio
 

SNESFAN

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If you missed what Exophase said: 4 GB of RAM would need *8* RAM-chips. That's a lot of chips.

It isn't really an option to go beyond 2 GB.

 

 

 you mean this?


 


Okay, apparently the OMAP5432 datasheet is way out of date on this, you can actually currently buy 8Gbit DRAMs with 16-bit interfaces, at least from Hynix. So 4GB w/4 DRAM chips is at least feasible.

 
besides, I'm not arguing what's possible, I'm arguing what the preference is. The possible based off the preference is what ED and gta04 will need to determine
 
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Rockthesmurf

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Genuine question (aimed more at technical types like Exophase, or anyone else who is knowledgeable at a low hardware level): how important is memory speed for these sort of devices? My understanding for desktop PCs, is that getting faster memory (say going from 1600MHz to 2200MHz) yields next to no impact on noticeable performance day to day. I am currently not clear if this is the same on devices like Pyra/Pandora, or whether memory is more of a bottle neck here (maybe it is a lot slower than PC and playing catch up)?

I am just curious as the poll asks whether people want fast memory or not.
 

xiongxioi

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How to make your PC run faster


Quick tip 101


1. Have enough memory so you would never need virtual memory.


2. Put all your os and frequently used softwares on your ssd or memory disk.


3. Profit


Memory speed is the one of the longer boards of the barrel, unless your PC is real high end, it would not have any noticeable impact what so ever.
 

Rockthesmurf

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@xiongxioi I have my OS and frequently used programs on an SSD and 32 GB of RAM; should I invoice you directly so I can get my profit now? ;) For what it is worth, I also have 2200MHz memory, but at the time I researched 1600 vs 2200 and my understanding 2200 makes basically no difference worth considering (I only got it as it was almost identically priced to the 1600 so thought I might as well play the numbers game).
 

slaeshjag

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How to make your PC run faster


Quick tip 101


1. Have enough memory so you would never need virtual memory.


2. Put all your os and frequently used softwares on your ssd or memory disk.


3. Profit


Memory speed is the one of the longer boards of the barrel, unless your PC is real high end, it would not have any noticeable impact what so ever.
A faster bus speed on the RAM generally has little effect on random access performance.
 

SNESFAN

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faster ram will make for better performance when memory bandwidth is the issue, large files and stuff like games or video editing

cas latency will effect things like random access from my understanding, but getting ultra low latency ram is rarely worth the price premium IMO
 

xiongxioi

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@steven craft


I'm curious as to what drives you to get that much memory? No program would ever use that much memory, unless you do lots of editing. That's impressive none the less. 4 channel 8gb 2200 memory is rather awesome. How did you get cheap 2200 memory sticks? Did you bought those from robbers?


I think number of channels is more important than bus speed. Not sure if 2gb would cut it for pyra's lifespan though. Perhaps we would all be watching 4k videos on YouTube in the future even in Australia. (Sarcastic undertone)
 

_wb_

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Connecting the big SD-cards to SATA with UHS-II might be nice.

How's the  power consumption of SATA compared to SDIO?

Don't want to waste Power.
I don't think storage without moving parts will make a real dent in the power budget, whether it is SD, eMMC or SATA. The idle power for all options should be quite close to zero, and the power when active (during transfer) will probably mostly depend on speed and the quality of the card itself -- faster will consume more power, but of course for a shorter amount of time. As long as we're not using spinning disks we'll be fine :)
If that's the case then I think I have my preferred setting:

(If everything fits onto the board and everything else works).

1: emmc 16GB via sdio

2: Micro SD and Sim card slot combined via sdio

3: Left SD-Slot with SATA and UHS-II pins

4: Right SD-Slot via sdio
Yes, that's also my preferred setup if feasible. I wouldn't mind having only 8GB of eMMC if there's an internal microSD slot too, and it does not have to be the fastest possible eMMC either since SATA will be faster anyway. If cost is an issue then the eMMC can be left out and it can be shipped with a cheap, small, but not too slow microSD card -- those who want more capacity or speed can upgrade the microSD card or if they really feel the need for speed, boot from the left SD slot to get even better speeds than what eMMC allows.

My preferred setup: what you describe above.

If only UHS-I through SATA is possible (not UHS-II), then this is my preferred setup:

1: very fast eMMC, 16GB or more

1: Micro SD and Sim card slot combined, microSD via SATA

2: Left UHS-I SD-Slot

3: Right UHS-I SD-Slot

Lower cost option:

1: Micro SD and Sim card slot combined

2: Left UHS-II SD-Slot via SATA

3: Right UHS-I SD-Slot

Even lower cost option, and certainly feasible (I'm not sure if we can actually find a component to do UHS-II through SATA):

1: Micro SD and Sim card slot combined

2: Left UHS-I SD-Slot

3: Right UHS-I SD-Slot

For RAM I think power consumption and capacity are the most important things; unfortunately those are conflicting goals so it will depend on the exact specs of the options what the desirable trade-off is. Does anyone have data on this?

I think 2GB is enough. I voted for 4GB because that is what I personally would want to have if the Pyra were designed just for me -- I don't really want more than that because I don't want to pay for it in terms of money and power consumption. But 2GB should be enough and I would certainly be happy with that, and since we need to have "one size fits all" here (upgradeable RAM is not going to be feasible) and price is an important issue, I think it's probably the best choice.

For internal storage, upgradeability is the most important thing -- if you have that, you can pick your own trade-off between speed, cost, capacity, power efficiency and durability. Either it is non-upgradeable and we have to make some kind of compromise, knowing very well that we cannot simultaneously get the best speed, lowest cost, biggest capacity, lowest power, and most durable solution. Or it is upgradeable and everyone can get something according to his own preference.
 

Exophase

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If you missed what Exophase said: 4 GB of RAM would need *8* RAM-chips. That's a lot of chips.

It isn't really an option to go beyond 2 GB.
To be fair, I did have to correct myself; with most recently available chips it should be possible to do it with 4. Even 4 sounds like a ton, it'd be great if they could do 2GB with 2 chips. But I don't know if the highest density chips are easy enough to purchase and are cost competitive (normally having fewer higher density chips should be cheaper though, not just in parts cost but in assembly, and it'd allow for a somewhat simpler board.. memory interconnect is one of the most complex part of board layout, not just because of all the traces you need but because of timing restraints)

Genuine question (aimed more at technical types like Exophase, or anyone else who is knowledgeable at a low hardware level): how important is memory speed for these sort of devices? My understanding for desktop PCs, is that getting faster memory (say going from 1600MHz to 2200MHz) yields next to no impact on noticeable performance day to day. I am currently not clear if this is the same on devices like Pyra/Pandora, or whether memory is more of a bottle neck here (maybe it is a lot slower than PC and playing catch up)?

I am just curious as the poll asks whether people want fast memory or not.
It's hard to say exactly, probably a lot of code has some simple streaming sections that will always be bandwidth bound, but for most programs this doesn't seem that common. If your bandwidth is too low eventually you'll start affecting other pieces of code too, and eventually the hit it has on latency will add up. But I don't think there'll be that big of a range of speeds available.

Like you said, going from DDR3-1600 to 2200 will give little to no benefit for most apps on, let's say, an i5-2500K. Ignoring the doubled core count, that'd be 3.7GHz vs 1.7GHz, and another rough 2x difference in perf/MHz, so we'll say at least a 4x difference in per-core performance. DDR3-1600 @ 128-bit offers a maximum of 25.6MB/s. OMAP5432 supports a 533MHz memory clock speed (DDR3-1066), offering over 8GB/s (2x32-bit interface), so I think this should be sufficient, even taking into consideration that Intel's memory controller is probably more efficient than ARM's.

However, any of the SoCs we use will also need to share bandwidth with the GPU. It's possible that the GPU will be bandwidth limited under some circumstances. It's hard to say exactly.

Saving RAM latency will probably not help that much, the latency imposed by the SoC tends to dwarf the latency once you get off chip.
 

Rockthesmurf

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@steven craft


I'm curious as to what drives you to get that much memory? No program would ever use that much memory, unless you do lots of editing. That's impressive none the less. 4 channel 8gb 2200 memory is rather awesome. How did you get cheap 2200 memory sticks? Did you bought those from robbers?
It is my work PC, I need about 8 GB just to link a project built with Crossbridge/FlasCC, and I typically work on a couple of projects at once, plus have some 3D mesh editing programs, plus 2D graphics editing packages open, a bunch of website tabs, so getting up to 16 GB isn't too hard. My machine is 12 logical cores, when compiling I want results as fast as possible, so our build system will spawn 12 compilers at a time, each one can eat up a GB each (when building large amounts of code), so while it might sound a little extra for casual users, for certain people lots of memory (and lots of CPU cores) is more common.

So far I haven't got close to using the 32 GB of available memory, but I've gone past 16 GB, so I am happy we went for 32 GB machines on our last upgrade cycle. In terms of price, we upgraded some servers last year, and memory seemed pretty cheap (32 GB of 1600MHz for 100 GBP), but one year later, the prices all seemed to go up (32 GB of 2400MHz for 210 GBP, and as I mentioned before the 1600MHz stuff was maybe 10 GBP cheaper, so nothing really in it). Oh, I didn't buy it from robbers, from ebuyer.com ;)

@Exophase thanks for the explanation; roughly matches up with my thoughts. Purely out of curiosity, can I run an application on my Pandora and see what the memory bandwidth being used is (roughly)? I typically find the GPU bottlenecks my own tests before the CPU, but it would be interesting to see what sort of memory bandwidth some intensive applications/games use.

EDIT: For reference, I just checked my memory usage right now, Windows says 14.5 GB, and I am pretty much idling at the moment (not compiling/building), just have a few programs open (including a Virtual Machine, which by itself is probably using up a good chunk of memory).
 
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Grench

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This UHS-II SD through SATA idea needs to be explored; even if we don't want it for the internal storage, it could be good to have it on one of the external SD slots. The speed of the SD slots is likely to become the limiting factor on the Pyra (like it was on the Pandora too) since cards already exist today that are faster than that. So it would be really nice if we can get a potential factor 3 speedup in this way.
If you're going to give SD on SATA serious consideration, then take a 2nd look at: http://www.d-broad.com/db300_eg.html

It can run TWO SD ports to the SATA connector. I.e. you could link both of the front SD ports to the SATA controller.

Booting off of an internal eMMC or microSD, those front facing ports could scream. They would still be mount/unmount capable - the system would simply see them as if they were removable hard drives.

Then we get into the hacker-fun territory. That bridge controller is also RAID capable. If someone chose to they could put two SDXC cards in, set the controller to RAID 0 or 1 and have a darn fast or failure protected 'desktop' machine. Not advisable for 'normal' users, but it'd be kind of cool 'just to do'.

I think it's still in the 'hold my beer and check this out' territory. We don't know how much work or space would be required to implement a http://www.d-broad.com/db300_eg.html type solution. The control chip is very tiny - but I'm not sure what else on their dev board would be required in a Pyra.

Still - the thought of having two front facing 200+MB/s SD ports gives me chills.
 
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