Topic: SD card speed

[Ray Carter]

I have read that some cards read and write faster than others. What do you use and why.

[Enufzed]

I use a Sandisk Extreme III 30Mg  4GB card for reliability and speed of recording and snapshots. it appears to be very compatible with HB units. The Sandisk card also comes with a one year subscription to Rescue Pro which is recovery software for digital media.
Regards
Geoff

[George]

Ray

Like Geoff, I also have the 4 GB SanDisk III SDHC card.  You can get cards up to 32/64 GB SD cards, I do not see a need for these large cards.  You can find them reasonably priced on the internet.  Also you will need a card reader to download/upload information from a computer.

George

[Humminbird_Greg]

Personally I use this one:




Okay that’s not real and was something I made to ‘one-up’ someone hear at work who was bragging about their new (at that time) faster and larger capacity SDHC memory card...
If you are going to be making Sonar Recordings, you will want to use the SD memory card with the fastest Read/Write speed so that the unit will be able to transmit/receive as fast as it can so the recorded sonar will be more detailed.  By using a slower speed memory card the sonar recording could be less detailed as the unit will have to wait for the data to be written to the memory card before it can save the next sonar transmit/receive cycle.

[sonar2000]

Wouldn't it be nice if the units could buffer the sonar data and then write to a card at given intervals.. this woujld help with some of the problems....I would also guess this would have to be for newer units.
chuck

[newkid4si]

The first card in this link may be of interest. Next step up from the Extreme III ? .....ie 45 MBs

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=san+disk+extreme+pro&x=11&y=34

[Humminbird_Greg]

Yes, that one would be even faster.

[sonar2000]

How about a hard drive on the unit..then after the recording is done write it to the SD...
Chuck

[Ray Carter]

Thanks for the input.
Am now using a cheep 8GB may up grade to a better one.

[pebe]

I believe that almost all Cards should be fast enough ?

For example:

3MB/sec means, ... 3MB x 60sec * 60Min, almost 10.8 GBytes for one Hour recording.
That is much, much more than a Recordingfile grows in one Hour.

And now lets say that the Unit writes sometimes more pings sometimes less.
Is this the Reason for needing a faster transfer than 3MB/sec ?

Could someone explain the thruely needed Speed for the Unit ?

[Del]

It might save recorded data to system memory first and then transfer the recorded file in parts to the card. Due to the transfer you might have performance issues on the device. For example: The unit is recording 10sec = 30mb, and then writing the first part of the recorded file to the card. On 10mb/s card it would need 3s on 30mb/s still 1s. At least some other equipment is working like this, so HB devices might be too.

Another theory:  the device is writing directly to the card, caching the files there and then compressing the files to the final result, which might end up in several read/write cycles.

Just my guesses, but lots of people with slow cards reported performance issues while recording. Additionally, if you use a 10mb/s card, you hardly will reach full speed, it will be more like 6mb/s, same for 20mb/s or 45mb/s.


Greetings,
Del