andyjenkins

I've done a bit of searching around this forum but not quite found the answer to my question.

I'm looking at getting a new SD or CF card .. fairly bigish in size, 2, maybe 4GB. Question is does the 4700's IO to SD and CF take advantage of the 9 and 20Mb speed afforded by the likes of Sandisk Ultra 2 and Ultra 3? I've found on the forum that the 4700's IO is about 3x .. but 3x what?

Can anyone categorically state that even a 1st gen SanDisk (or similar) will be no slower than the Ultra 2 or Ultra 3 in an 4700? Again, found in searching, I've seen the only (and I mean, the only reason for taking Ultra 2 or 3 is for when you use it in a card reader to copy / read files etc - when its in the 4700, its no faster than any other (slower) card on the market - because of the hardware limitation in the 4700.

I'm assuming that there's no speed differential between CF and SD here - right ?

blueradish

Hey Andy, little tight for time right now or I'd find some for ya. Do a search at the top on CF SD card speeds, there are a number of threads covering this.

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wackyd

using pocket mechanic to bench:

SD card (Kingmax Platinum, 66X rated via USB reader):

avg write: 0.02 MB/sec
avg read: 0.86 MB/sec (beaut for loading up large files/databases)

CF card (Sandisk EXTREME (avoid this rubbish at all costs), 66X ?)

avg write: 0.04 MB/sec (I can use this POS to cache ie files)
avg read: 0.37 MB/sec

Some notes (sorry I am in a hurry):

1. The CF port is meant to be faster than the SD port for both read and write
2. You will never get the speeds marked when using the cards on a PDA - the I/O ports are the bandwidth limiting factors
3. On that note you can get close to the full read write speed on a USB or FireWire memory card reader
4. Avoid sandisk if you can. A lot of people (myself included) have had bad experiences with cards that were either DOA, or have started to fail after a few months.

I have a Lexar high speed card waiting at the post office for me to pick up when I have the time, and i'll post the benchmark results for that one too.

cheerio,

wackyd

alan sh

I hate to disagree but I have 2 1Gb SANDISK Ultra II cards for my Canon 20D and they perform very very well. Just because you have had bad experiences doesn't make them all bad.

So, if you can tell me where to get Pocket Mechanic -found it, I'll also try this test and let you know - I have a variety of SD and CF cards here.

Alan

alan sh

Humm - I may have to eat some humble pie here.

My SANDISK Ultra II performs the worst of all my CF and SD cards at reading and is almost the slowest at writing.

But this does not equate to what I can see when I use my USB card reader. The Sandisk card flies when copying my photos off.

Can anyone explain this ? I can't.

Alan

andyjenkins

Why is it when you've got your mind set on something, someone throws a stone in the works and says something bad about the thing your about to purchase.

Are SanDisk really that bad? Didnt get that gist from the threads I've read on various forums.

WackyD, I'm supprised you only achieved avg read: 0.37 MB/sec on the Extreme card - they're supposed to be 133x .. 20Mbps.

ShALLaX

I guess the cards I bought are pretty good.

With Sectors/block: 64 (Variable unchecked):

SD (Sequential + Random):
Read: 1.22MB/s
Write: 0.65MB/s

SD (Sequential):
Read: 1.57MB/s
Write: 0.64MB/s

SD (Random):
Read: 1.00MB/s
Write: 0.65MB/s

CF (Sequential + Random):
Read: 1.27MB/s
Write: 0.16MB/s

CF (Sequential):
Read: 1.77MB/s
Write: 0.16MB/s

CF (Random):
Read: 1.02MB/s
Write: 0.16MB/s

These are the "Standard" 1GB SanDisk SD and 1GB SanDisk CF cards. Despite them both being SanDisk, I've never had any issues with them... with SanDisk you expect the highest quality since they invented the things! (Well, not CF).

»HunTeR«

How about microdrives?
I am much more intrested in writing speeds than in reading... will i gte better speeds at microdives? (probably at the cost of energy consumption)

wackyd

Originally Posted by andyjenkins

WackyD, I'm supprised you only achieved avg read: 0.37 MB/sec on the Extreme card - they're supposed to be 133x .. 20Mbps.

Andy, the 133X quoted is the theoretic speed at which they can be written / read from using a reader/writer that is capable of addressing the memory at those speeds.

With PDA's, the input/output ports for the memory cards is much much slower at writing to the cards than a USB 2.0 reader is on a PC.

wackyd

Originally Posted by »HunTeR«

How about microdrives? I am much more intrested in writing speeds than in reading... will i gte better speeds at microdives? (probably at the cost of energy consumption)

If my memory serves me correctly, the sustained read/write speeds of the microdrives are quite good - but - this will only serve you well when you write or read large files (eg movies).

But for everyday use, they can be slow as they take time to spin up. They won't beat the solid state CF cards.

alan sh

SOme results for you to think about. You must make sure you exit the test and restart between each test - otherwise the results can be off (I have no idea why).

All results are for read and write using sequential and random and fixed sector size:

1Gb Sandisk Ultra.
read 1.71
write 0.85

1Gb Keymem 60x SD card
read 1.72
write 0.85

512Mb Peak Ultra SD card
read 1.66
write 0.95

256mb Peak CF card (Samsung inside)
read 1.83
write 1.13

256Mb Viking CF card (Samsung inside)
read 1.71
write 0.84

256Mb Viking CF card (Toshiba inside)
read 1.78
write 0.25

512Mb Xtra Green CF card (Toshiba inside)
read 1.70
write 0.21

340Mb IBM Microdrive
read 0.89
write 1.37


Conclusion. Toshiba powered CF cards are bad at writing. Other than that, the limitation seems to be the I/O of the 4700. The variation of the others is not significant - apart from the microdrive which seems to be able to write very very fast (caching maybe ?)


Alan

alan sh

Updated the list with results from an IBM microdrive

Alan

3715y

Micro drive are indeed small size harddisk.....which need some time to reach its full speed just like the lift...

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»HunTeR«

I heard that some microdrives consume a lot of energy ... they kill the bat. !

anyone faced this problem?

3715y

My friend DV use Microdrive. The battery got sucked up in a short while. The movie recording time no longer limited by the card size but the battery life.
: (

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