Boot By Sd Card Speed


meandu229

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After alot of fighting with partitions I have my 8gb class 2 card bootable, but its quite slow to boot and then bit laggy in the interface, is it worth installing on my 16gb class 10, will it be a big difference?
 
Probably worth the trial for comparison, as some may not have a class10 to already report back back on. Hope it works better if you bother :)
 
Depends on the brand it seems. Some brand's class 10 is not much faster than their class 6. Is it really that slow on a class 6?

Oh wait, I just wrote that thinking you were trying with a class 6. I'm sure you could go with even a class 6 and see a huge improvement over class 2. Right now the brand I buy, Transcend, class 6 and 10 are about the same price.
 
meandu229 said:
After alot of fighting with partitions I have my 8gb class 2 card bootable, but its quite slow to boot and then bit laggy in the interface, is it worth installing on my 16gb class 10, will it be a big difference?
I'm using a class 6 card with a bunch of extra stuff installed it seems to boot the same time as internal flash

In addition copying via ssh over usb I got 1.9MB/s copying *to* the sd card and 2.0MB/s copying to /dev/null

Having recently added NAT mangling so I can browse over the internet my transfer speed has dropped to "only" about 1.7ish MB/s...

These apparent speeds are only seen on large files obviously bulk copying lots of small files in a hierarchy is slower

... so basically I think class 6 is as fast as the Pandora practically needs - but I'd be happy to be proved wrong!

edit: don't forget not all sd cards of the same class preform exactly the same - there are naff ones so experiment with borrowed cards till you find the right brand/performance/price mix

I'm using a sandisk "extreme" 8gb to boot from (quotes 20MB/s lol it has an asterisk* !) I use a smaller class 4 with it for mp3's etc
 
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typs lik dis said:
What makes you think SSH over USB isn't the bottleneck there?
nothing it is the bottle neck, but if its fast enough to keep up with that, it's more than fast enough... I seriously doubt if anything faster would significantly increase boot speed
 
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There was a related thread on the Pandora boards:
SD Cards and Speed

In short, the read speeds for just about any card class rating are not really affected. The class ratings of the SD cards only affects (minimum)write speeds. In other words, the class of the card will not affect load speeds.
 
Natro said:
There was a related thread on the Pandora boards:
SD Cards and Speed

In short, the read speeds for just about any card class rating are not really affected. The class ratings of the SD cards only affects (minimum)write speeds. In other words, the class of the card will not affect load speeds.
thats not what I've seen, my craptastic camera sd card (class 2) is defiantly slower at reading than my class 6 - saying all cards have identical read speeds is simply not correct
 
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Chris is right. The class system defines the minimum *write* speed. While it doesn't guarantee that read speeds will be faster, they usually (always?) are.
 
chris_c said:
thats not what I've seen, my craptastic camera sd card (class 2) is defiantly slower at reading than my class 6 - saying all cards have identical read speeds is simply not correct

I did not intend to assert that all read speeds of SD cards were identical. What I meant was that in the testing done by others with SD cards and their Pandoras (and posted in the linked thread) there did not seem to be any significant difference in read speeds. In general they all seemed to read in the 15Mbps ballpark on the Pandora regardless of SD card class rating.
 
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Natro said:
chris_c said:
thats not what I've seen, my craptastic camera sd card (class 2) is defiantly slower at reading than my class 6 - saying all cards have identical read speeds is simply not correct

I did not intend to assert that all read speeds of SD cards were identical. What I meant was that in the testing done by others with SD cards and their Pandoras (and posted in the linked thread) there did not seem to be any significant difference in read speeds. In general they all seemed to read in the 15Mbps ballpark on the Pandora regardless of SD card class rating.

I read through the other thread and the results there are hardly definitive - and from what I can tell they do not tell the story that you are telling here.

All I really saw was that different cards behave differently on the controller in the Pandora. How the test is set up has as much to do with the performance as the card itself.

Previous threads show that the Pandora has a theoretical speed of up to 20MB/sec through the SD card connector.

The real way to settle this particular question (SD card boot speed) is for someone to create an SD boot image, place that on several cards and try it.

This question probably will not have a real answer until there are a lot more Pandora consoles actually in the hands of users. Some day when I have mine and can get the SD card boot image working, I'll try it on some of the dozen or so SD and SDHC cards that I have. I ordered Oct 1st, 2008. Still waiting.
 
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