Couple Questions About Sd-Memory

[lollebol]

Hello all,
my nickname is lollebol, and i'm quite new here but long enough to be in the first batch. :rolleyes:

I'm looking for a SD(HC) memory card for with the pandora to store music/videos/games. As you all know, there are several classes and speeds, where higher specifications are more expensive.

What is the maximum read speed of the Pandora for SD Memory cards?
Will the user notice the different between speeds like 6MB/s, 15MB/s and 30MB/s capable cards?
And does the speed affects the performance for certain applications like the emulators?

Sorry if this is already been answered but I have tried using the search button but I couldn't find a good answer.

With kind regards,

Lollebol

 

[Vlynndar]

There should be some info in this thread.

Also, for search, you'd need to use advanced search, not the normal one. Annoying.

 

[gruso]

Also, the Pandorian's guide to SD cards: http://pandorapress.net/2009/11/06/the-pandorians-guide-to-sd-cards/

 

[lollebol]

Thanks for the fast reply's!
I've read both links but unfortunately there are only speculations and not exact answers.
Are the developers active on the forums? They might know it :rolleyes:

 

[Nintendo]

Yeah, mate, they are. Although email is better...so send EvilDragon or craigix an email. andora2ut4: B)

 

[mali]

SONY is joking

 

[aesir911]

basically don't buy chinese (too bad the pandora team didn't realize this), and try to get a class 6 sdhc card...

 

[droneb]

basically don't buy chinese (too bad the pandora team didn't realize this), and try to get a class 6 sdhc card...

ye ye yeah.

http://news.cnet.com/Dell-Exploding-batteries-are-Sonys-fault/2100-1005_3-6115710.html

buy japanese they have a warmer outburst when they fail.

see, its not a hate china products but a point of view.

you can also find excellent products made from china it all depends!.
you get what you pay for.

 

[Nintendo]

Try to avoid buying from eBay.

That is all.

 

[gruso]

Thanks for the fast reply's!
I've read both links but unfortunately there are only speculations and not exact answers.
Are the developers active on the forums? They might know it :rolleyes:

From that thread:

More verbosely, MWeston stated at one point that the maximum SD speed that could be achieved was 24 MB/s (I can't find the post now - the board only records the last 200 posts by MWeston, and Google is unhelpful, though it does show results in which people discuss that number). Someone else (ED?) stated that he had at least one card that would do 15 MB/s.

I know that's not as good as a real source link (Tom might be remembering it incorrectly, who knows) but FYI, MWeston is the hardware developer (which you probably know) and Tom is a pretty switched on person. I'd rate his post somewhere above speculation, even though it's not from the horse's mouth.

My own advice is, it's probably not worth spending top dollar on a Super Ultra Class 10 monstercard. In my experience on the GP2X, a Sandisk Class 2 card was more than sufficient to run any homebrew or emulators that I threw at it. I'd get the occasional "stutter" in some emus, but I can't really say if that was read speeds or the code itself.

I've gone with a new 16GB Class 6 Sandisk card for Pandora. I don't think there's any point spending more than that (except for a 32GB Class 6 of course).

 

[Tom`]

Thanks

In fact Chip did figure out how to search older posts:

Unfortunately, I can't find the post, because for some reason MWeston's post history apparently only includes either a certain number of posts, or only posts back to a certain time. Google was similarly unhelpful - maybe problems caused by the board upgrade.

To avoid the cutoff, you have to do an advanced search and specify a date range. I just set it to between 2003 and now.

24MB/s based on a 48MHz clock, 4 bit SDIO

24 MB/s is the theoretical upper limit, though it hasn't been (IIRC) officially and unambiguously stated whether the SD cards share the same bus, so it could be either a total of 24 MB/s, or 24 MB/s per slot.

 

[alucart1984]

Thanks for the fast reply's!
I've read both links but unfortunately there are only speculations and not exact answers.
Are the developers active on the forums? They might know it :rolleyes:

People are running emulators and such with their GP2X, Wiz and Dingoo just fine with Class 4 cards. Also those links are not ONLY speculations its taking facts about the cards and appling that to the Pandora. In other words, a class 6 card would ensure that you have fast enough read/write speeds that you didn't get any hiccups/lag in programs/games on the Pandora. It's as simple as that.

 

[lollebol]

Ok thanks all for the usefull replies, this saves me a couple of bucks!

 

[Mr.Gonzo]

Since this thread is likely to disappear pretty fast.
And that browsing through the advanced search results at work is counter productive ( and that i am pretty damn lazy ).

I have a noobish question concerning SDHC too.

Will it be possible to Change/Delete content on the fly?
Like transfer stuff from the SD cards to an External Hardrive and vice versa?
Would it be relatively fast? (or you could just leave the panda transfer stuff plugged to the HD in your bag... if possible)
This would completely erradicate the need for multiple SD cards.
(Two being more than enough, one for software, one for stuff and media)

kthxbye

 

[Exophase]

24 MB/s is the theoretical upper limit, though it hasn't been (IIRC) officially and unambiguously stated whether the SD cards share the same bus, so it could be either a total of 24 MB/s, or 24 MB/s per slot.

They don't share the same bus.

 

[urjaman]

Will it be possible to Change/Delete content on the fly?

*sigh* Why would it not be able to?

Like transfer stuff from the SD cards to an External Hardrive and vice versa?

As long as the external hard drive can work with the 500mA USB supply given by the pandora,
there was a thread about that recently, many cant. 1.8" drives are your best bet.

Would it be relatively fast?

I think the limiting factor will be the pandora SD controller and/or your SD card speed;
15 MB/s has been measured (IIRC with a beagleboard), 24 MB/s is theoretical bandwidth.

 

[Vlynndar]

24 MB/s is the theoretical upper limit, though it hasn't been (IIRC) officially and unambiguously stated whether the SD cards share the same bus, so it could be either a total of 24 MB/s, or 24 MB/s per slot.

They don't share the same bus.

So on the question of raid0..?

 

[Mr.Gonzo]

Will it be possible to Change/Delete content on the fly?

*sigh* Why would it not be able to?

Like transfer stuff from the SD cards to an External Hardrive and vice versa?

As long as the external hard drive can work with the 500mA USB supply given by the pandora,
there was a thread about that recently, many cant. 1.8" drives are your best bet.

Would it be relatively fast?

I think the limiting factor will be the pandora SD controller and/or your SD card speed;
15 MB/s has been measured (IIRC with a beagleboard), 24 MB/s is theoretical bandwidth.

hehe if the first question sounded a little silly it's because it was mostly an introductionary one.

For the rest, thanks.

So if i was to transfer a 700mb movie from external HD too the panda it would take around 47 seconds with a decent SD card, that's it?

 

[WizardStan]

So if i was to transfer a 700mb movie from external HD too the panda it would take around 47 seconds with a decent SD card, that's it?

A class 2 card "guarantees" that a 700mb file can be written to the SD card in about 6 minutes or less, a class 6 in about 2 minutes or less. There's no card that will "guarantee" a 700mb file can be written in 47 seconds.
I write "guarantee" because that's what the class rating tells you: the absolute minimum write speed. Most cards, under normal conditions, do a lot better. Even that class 2 can probably write your 700mb in a couple minutes. So unless you absolutely need to write a lot of really large files in a fairly short period of time where every extra minute counts, even a cheap and slow card should be sufficient.

 

[Mr.Gonzo]

well i was planning on getting class 6 anyway.
It's that if i really feel the need to watch some movie on the go that i don't have on an sd card. I could just transfer it presto, unplug the external hard drive and watch it. Saving lots of battery life.